
St. Gregory of Nyssa is one of the fourth century Cappadocian Fathers. St. Gregory hails from a holy family of saint siblings, including St. Basil the Great and St. Macrina. Dr. Chris Mooney shares about the life and scholarly work of St. Gregory and how he continues to inspires us today!
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Podcast Narrator
You're listening to a podcast on Catholic Saints. This podcast is produced by the Augustine Institute, an apostolate helping Catholics understand, live, and share their faith.
Mary McGeehan
Hello. Welcome to Catholic Saints. My name is Mary McGeehan. I'm joined by Dr. Chris Mooney, the. Thank you for being here.
Dr. Chris Mooney
Thanks, Mary.
Mary McGeehan
Welcome to this episode of Catholic Saints. We're going to dive into the life of St. Gregory of Nyssa, whose feast day is January 10th. My first question is, where is Nyssa? Am I pronouncing that right?
Dr. Chris Mooney
Yes, yes. Nyssa. Yeah, yeah. He's called either Saint Gregory of Nyssa or sometimes Saint Gregory. Nyssen.
Mary McGeehan
Nyssin. Okay.
Dr. Chris Mooney
Yeah. But Nyssa was in modern day Turkey. So Gregory of Nyssa is known as one of the Cappadocians, the three classic. These three classic saints and theologians called the Cappadocians. Basil of Caesarea. That's where he was. Bishop. Gregory of Nyssa, where he was Bishop. And Gregory of Nazianzus. Nazianzus.
Mary McGeehan
Referencing just the locations, the locations where.
Dr. Chris Mooney
They were these three bishops who all knew one another very well. They all lived in this area, Cappadocia.
Mary McGeehan
At the same time period.
Dr. Chris Mooney
Southern Turkey in the same time period. Yep. In fact, as I'll mention in a moment, Basil and Gregory of Nyssa were brothers. They knew each other. Basil and Gregory of Nazianzus were best friends. Oh, no. Close connection between all of them.
Mary McGeehan
Saints. Common clusters.
Dr. Chris Mooney
The saints come in clusters. They all lived in the 4th century at this great period of flourishing in early Christian theology. This is the time period of the Council of Nicaea. This is the time period where at the start of the fourth century, the very beginning of the fourth century, the empire. Christians in the empire are just getting over some of the worst persecutions that have ever taken place. We sometimes think that maybe, oh, you know, the first century or the early second century, the very beginning was the worst. No, it was the third century actually had the worst persecutions. So the beginning of the fourth century, the three hundreds, we're looking at. On the one hand, being a Christian is just coming out of this period of great persecution. By the end of the 4th century, the all the emperors are Christians and Christianity is the official religion of the Roman Empire.
Mary McGeehan
Fascinating time period.
Dr. Chris Mooney
Yeah. Hugely important time period. Council of nicaea is in 325. Council of Constantinople in 381. These are where we get our creed from. So hugely important. And this is in the east and in the West. But St. Gregory of Nyssa is one of these key figures from the 4th century during this golden age of patristic theology. He was born around 335, lived until 395.
Mary McGeehan
Do you think it became a golden age? Was the golden age after the persecutions? Is that so?
Dr. Chris Mooney
Yes.
Mary McGeehan
Okay. So was it, you know, finally they had time to start really debating theology that were.
Dr. Chris Mooney
No. That's a great question. I think there's a lot of different things. I think the church had expanded so much. I think, yeah, it was possible to have. Maybe there was more freedom for open debate. I also think there was a nice flourishing of Christians who. Who received a great classical education and then were able to take it into a deeper understanding of the faith. And Gregory's a great. Actually, all the Cappadocians are a great example of this, although Gregory himself was actually a homeschooler. So if anyone is listening and is homeschooling or was a homeschooler, you can enjoy thinking about Gregory. Gregory was from this big Catholic family, 10 children in total. Classic big Catholic family. Many of them actually are saints. Gregory's older brother, Basil is a saint. Gregory's older sister, Macrina is a saint. And Gregory actually is. In some ways, many people think of him as the most. As one of the sharpest, subtlest, and most philosophically equipped of the Cappadocians. But he received the least formal education. He was mostly taught at home by his older sister, Macrina, who's also a great example. So, again, if anyone. Anyone who's interested in homeschooling should ask the intercession of Gregory's older sister, Macrina. But Gregory grew up.
Mary McGeehan
Were you homeschooled?
Dr. Chris Mooney
No, I was homeschooled. Sorry, that's not why I'm mentioning that. Just in case. Just in case anyone wanted a shout.
Mary McGeehan
Out to a great patron for big families.
Dr. Chris Mooney
Yeah, from a big family. They had a reputation, or we get the impression that they were a very ascetic family. Basil founded some of the first hospitals. Macrina was known for taking in abandoned children. But at the same time, they were also a very warm family. Many of them committed to a kind of monastic way of living. Gregory of Nisid, we think he probably did marry, though it looks like his wife passed away when. Very early on in their marriage and that they didn't have any children. Maybe she died in childbirth. It's unclear. But he committed to living a very monastic life from that point on.
Mary McGeehan
Did he become a priest ever?
Dr. Chris Mooney
And he did. He became a priest and a bishop and was the bishop of Nyssa for, I think, about 20 years from the 370s to the 390s when he died. And it was also in that period. That's where we know the most about Gregory from, because he was a very accomplished theologian and a preacher. Gregory actually stands out as a preacher in a lot of unique ways. You know, one thing, if people want to know something else remarkable about Gregory, Gregory was not just one of the first Christian, but maybe one of the first abolitionists in all of history. So I know this is a kind of. This is, you know, a topic that's difficult to wrap our minds around, how integrated slavery was into the ancient Roman world. Sometimes it's easy to forget, but it was part of all ancient societies. What makes Gregory stand out is that not only as a Christian, but there really was almost no one before Gregory who ever questioned this. And Gregory, in his preaching, is really the first witness we have in the long Christian tradition of proclaiming that slavery was an offense against God. And part of the reason, though this is, I think, so interesting about Gregory, you know, how did he think about this social mission? It's because this comes from his understanding of Christ. Gregory preaches that Christ has taken on the form of all humanity. He became as a slave, he became as a servant, he became as one poor. Because of that, we can see infinite dignity in all human beings. This is something that no philosopher ever proposed before. I think also a beautiful reflection of this is the fact that when Gregory writes a biography of one of his siblings, he writes the life of Macrina, not the life of Basil, his older brother. Basil is a great saint, but Gregory wants to highlight Macrina, his sister. You know, if you look at the great lives in Roman history, they're all focused on great statesmen. Who does Gregory think he wants the world to know about? His sister Macrina. And the life of Macrina is really beautiful, but Gregory wrote it because he thought that Macrina was an icon of Christ. So Gregory, and she was the primary.
Mary McGeehan
Educator of him as well, which is a sweet, sweet touch, too.
Dr. Chris Mooney
So Gregory, you can see how, as a pastor, how he cared about people because of how he thought about Christ. You mentioned we were talking earlier about, you know, what's different in the 4th century, and this kind of Christian ideas made such an impact and was so remarkable and transformative and revolutionary. No one had ever thought this way before.
Mary McGeehan
Interesting. You know, his mind was so conformed or was conforming to the mind of Christ, that from that, like you said, is where he was able to reflect on the social or slavery or social realities of the time period.
Dr. Chris Mooney
And project on him, that his sister stands out not because she was wealthy or because she was powerful like, you know, or because she was an accomplished writer. These are the sort of things that would make for prestige in the Greek and Roman world. She stood out because she was holy and because she was configured to Christ. And Gregory saw that.
Mary McGeehan
So that is fascinating. Well, you said he was a part of this golden age. So what are some of his most popular preaching teachings and what was he heavily involved in in the church at this time? Period?
Dr. Chris Mooney
Yeah, Gregory was a great theologian, a great defender of the Trinity, you know. So this is if we think of this period as when where our creed comes from, the same creed that we say every Sunday at Mass. Gregory played a major role in defending the creed and in participating in the council that helped to define the creed. And one of the things. So that's one thing that Gregory is known for, another thing that Gregory is known for. That may sound a little heady, but he is a theologian, after all. So hopefully people can bear with me on this, but I think this is a profound thought. Gregory in his writing, particularly talked about what we mean, what it means for God to be infinite. Okay, this may not have struck people before, but in the ancient world, in ancient philosophy, usually infinity was a bad thing.
Mary McGeehan
Really?
Dr. Chris Mooney
Infinity means. For a lot of ancient thinkers, infinity means lack of boundaries, being without restraint. Numbers are nice. 1, 2, 3, 4. They have distinct shape. Infinity is undefinable. It's chaos. Exactly. Gregory recognized that. No, it's the other way around, that God is infinite. We take this language for granted. We think of God as infinite, but actually that kind of language doesn't show up in the Bible. But this is one of the things that a lot of theologians today appreciate about Gregory, that he has a sense of the infinity of God. What does this mean for us? One of the things that we can cherish, that we cherish, even if it doesn't always come to the surface. But in all our thinking about God is that everything that God is, he is infinitely. When we love that God is good. Other people are good, but they're finitely good. There's some amount good. God is endlessly good. Other people console us. God is endlessly consoling. Other people teach us God is endlessly our teacher. And other people bring us joy. God is infinite joy. God is an ocean, an infinite, endless ocean of joy. And Gregory in his theology, although it can be hard to work through, but Gregory in his theology helps us to see this. That's what makes God different, That's what makes our Christian worship different than our relationship to anything else. That other things are finite. Even the people we love as much as we love them as much as they love us is a drop in the ocean compared to the infinite love of God. And Gregory has such a profound sense of this. He has such a profound sense too, of how heaven he writes about, at the beginning of his great commentary on the life of Moses, he writes about how heaven is a continuous entrance into that infinite goodness that is God.
Mary McGeehan
That's beautiful. Thank you. I'm going to take that to prayer. Especially when you're, you know, after confession or you're realizing, what am I attached to or what are the, you know, the idols in my life that I am grasping for, for that love or whatever you're ultimately hungering from God.
Dr. Chris Mooney
Because I'm infinite. Yeah, yeah. And Gregory really gets that. That wasn't. That's an idea that I think it takes great theologians. We can appreciate it now maybe in a simple way. It takes great theologians like Gregory to help understand.
Mary McGeehan
Yes.
Dr. Chris Mooney
But I have some other examples too, that are maybe a little more down to earth, and that's from this collection. This is Gregory's homilies on the Lord's Prayer and the Beatitudes. I mean, these are some of our most treasured texts in the Gospels. And Gregory wrote. Gregory, I shouldn't say wrote. Gregory gave this great series of homilies on the Lord's Prayer and on the Beatitudes. It really shows you him as a pastor. So this is. Anyone who wanted to can read these. This is from a series called Ancient Christian Writers. And the title is just the Lord's Prayer and the Beatitudes by Gregory of Nyssa.
Mary McGeehan
One question I had for Gregory, was he more a preacher or a writer or both?
Dr. Chris Mooney
Both.
Mary McGeehan
Okay. So a lot of what we can read today, I'm assuming, is a combination of his homilies and others. Yeah. Did he always write for his writing to be preached or were some independently?
Dr. Chris Mooney
That's a good question. Yeah. So, okay, so we've got great homilies by Gregory like these, another text which I didn't bring today, and maybe I should have, but another great text of Gregory's is called his Catechetical Oration. It looks like it's probably for baptism, but it's kind of like a 20 to 30 page introduction to the Christian faith from Gregory's perspective, you know, 4th century take on how to introduce the Christian faith to new beginners. Gregory also has spiritual writings like his Life on Life of Moses, which looks at Moses in the book of Exodus and uses Moses as a model for our spiritual growth. And Gregory is also known for treatises he wrote, like a series of treatises. He wrote against Eunomius. Eunomius was someone who was denying the doctrine of the Trinity.
Mary McGeehan
Yes, wonderful.
Dr. Chris Mooney
But this. I was just going to share some examples of his homilies. Yeah. So this is on the Lord's Prayer. Okay. Here Gregory's talking about prayer, so things we can think about. What does Gregory have to say about prayer for us? He says, therefore we must first of all. Again, he's commenting on Matthew in the introduction of the Lord's Prayer. He says, therefore we must first of all learn first of all, as the Lord says, that we ought always to pray and not to faint. For the effect of prayer is union with God. And if someone is with God, he is separated from the enemy. Through prayer we guard our chastity, control our temper and rid ourselves of vanity. It makes us forget injuries, overcomes envy, defeats injustice, and makes amend for sin. Through prayer, we obtain physical well being, a happy home and a strong, well ordered society. Then he goes on to say, prayer is intimacy with God and contemplation of the invisible. It satisfies our yearnings and makes us equal to angels. Through it, good prospers, evil is destroyed and sinners will be converted. Prayer is the enjoyment of things present and the substance of things to come. I love how he describes prayer. You know, Gregory recognizes he starts off the beginning of his homily on prayer and he says something that I'm sure all of us can relate to today. He says, I see that in this present life, men give their attention to everything else. One concentrating on this matter, another on that. But no one devotes his zeal to the good work of prayer. And so when Gregory tries to give a definition of what prayer is, he wants people to see prayer isn't to see God. Prayer is enjoyment of things present and the substance of things to come. We should love to pray. We have to learn to love to pray. But I love what Gregory says about prayer. I had one other passage I was going to bring.
Mary McGeehan
Yeah, I love that.
Dr. Chris Mooney
That's great on prayer. So again, I'm also also reading this to recommend it to anyone who's listening. Here's Gregory on the Lord's Prayer. What does it mean when we say hallowed be thy name? I think a question that many people, you know, maybe we haven't thought about it. We've prayed the Lord's Prayer so many times, maybe if you've prayed it every day, you might think, I prayed the Lord's Prayer 10,000 times. Yes, it's a lot of times. But to stop and think, what does it mean? So he says, if God rules all things and nothing can be added to his holiness, since he is in all things, absolutely perfect, what does it mean to pray? Hallowed be Thy name. Thy kingdom come. Perhaps by using such form of prayer, the word Christ intends to set forth something like this. Namely, that human nature is too weak to achieve anything good, and that therefore we can obtain nothing of the things for which we are anxious unless the good be accomplished in us by divine aid. And of all good things, the most important for me is that God's name should be glorified through my life. But perhaps our meaning will become clearer if we start from the opposite end. Then he goes on to talk about the rest of the prayer. But what does it mean? Why do we pray? Hallowed be thy name. It's not because God needs to become more holy. It's because we need to become more holy. We want God's name to be hollowed in us. But we have to ask this in prayer because we realize that no good can come to us or that all good comes to us by God's help. No good can come to us without God's help. And so the most good thing that we want. He says, the most important thing for me is that God's name should be glorified through my life. Namely, that in me. Hallowed be Thy name. And so that's what it means.
Mary McGeehan
That's beautiful. Thank you. And all the divine aid. I love that line. All good things come from the. Yes. God's assistance which you can glorify in your life. It's like man fully, or man fully alive has the vision of God.
Dr. Chris Mooney
Yes, In a similar way. Yeah. That's a great line from St. Irenaeus, the first doctrine of the Church. The glory of God is man fully alive. The life of man is the vision of God. All the fathers had a great sense of that. What is our highest joy? What does God want for us? And what is our highest joy? It's the vision of God. But how does this relate to the glory of God? It's that at work in us. So that's what it means for God's name to be hollowed.
Mary McGeehan
Thank you. This is very pastoral. Was he as a bishop and a priest and, you know, preaching the Trinity? What? I guess, were the people just craving this pastoral application of the teachings of the Church of This time period or, you know, what were the heresies that he was trying to pastor and jeopardize people from at this time period that also give context for why he was preaching and writing on these topics?
Dr. Chris Mooney
Yeah, great question. So one of the reasons I recommended this, this text is because, you know, Gregory, even though, okay, in one sense, this was a golden age of theology, but Gregory also, as a pastor, he faced the problems that pastors face of every time, you know, that people's hearts were divided and that their minds and understanding were divided. So one of the things that Gregory saw as his role as a pastor, as a bishop, you know, bishops in the 4th century, the main thing that they did day in, day out was to preach. That was the major thing that they did because they were the primary teachers. And so Gregory saw that one of his roles is to teach. So why does he write spiritual texts to help shape people? Why does he. Why does he preach? It's to help people understand. It's to help move people. You know, he has Gregory's good rhetoric. You know, if you read his homilies on the Lord's fairy thing, he's. These are pretty good. But he uses that. He uses that ability that he has in order to help teach people, in order to sway them. You know, he mentions, as I said at the start of his homily on the Lord's prayers. Look, I know that people don't pray. I know that this is a struggle for you. I know that it's hard to be consistent about this. Let me try to show you how good it is to pray.
Mary McGeehan
Yeah. The beauty of it.
Dr. Chris Mooney
Yeah. And so in that way, that's why I say that Gregory faced the same problems that pastors of every age face now. There were some. There's some. In some ways, though, Gregory also faced different problems. And one of those was a lot of confusion about the divinity of the Lord, the divinity of Jesus. There was. So in the early 4th century, we see the rise of the heresy called Arianism, that denial that Jesus is equal to the Father as God, you know, area. So the Council of Nicaea, where we get the Nicaean creed from, responds to this. But actually, after the Council of Nicaea, things became worse, not better.
Mary McGeehan
Okay.
Dr. Chris Mooney
Kind of interesting, maybe two for us to recognize. Historically, councils, usually in the history of the church, don't make things better all at once. They actually usually get worse, and then they get better afterwards.
Mary McGeehan
People are disgruntled.
Dr. Chris Mooney
People are disgruntled. Yeah. So before the Council of Nicaea, there were. Well, I should say, after the Council of Nicaea, there are major bishops who are Arians, there are Roman emperors who are Arians, or major members of the Roman aristocracy. So, okay, this is very difficult. And then you get what sometimes people think of as, like, hard Arianism in someone like Eunomius. Eunomius was a 4th century figure whom Gregory wrote against. I mentioned. He writes these treatises against him. And Eunomius took a very hard line that Jesus is absolutely not like the Father. You know, the Father is truly God and Jesus is not.
Mary McGeehan
Yes.
Dr. Chris Mooney
And so part of what Gregory does is respond to this, but he also knows the doctrine of the Trinity is hard to understand. So one of Gregory's classic texts is another one called To Oblabius. Oblivius was the name of this person he wrote to. It also goes by the title on not three Gods. You know, when we say that the Father is God and the Son is God and the Holy Spirit is God, how do we not mean there are three Gods? Gregory knew that this was hard for people to understand, so he writes this classic text to clarify what we mean.
Mary McGeehan
Interesting. Yeah. I'm just struck and so grateful for these great minds in this trailblazing season. Although the teaching has never changed, it's the minds to really help articulate. These are the parameters and boundaries of, you know, within. And these teachings on that were being discussed in Constantinople and Nicaea and this time period.
Dr. Chris Mooney
Yeah. And it's part of the difficulty is new questions come up, new problems come up, new ways of wondering about some issue. And that's when we really are grateful for great saints and theologians like Gregory.
Mary McGeehan
Yes, this is a sillier question, but how do we, like, Declaration of Independence, People have signed their names on that document. How do we know who was at these councils? Oh, yeah, Is it just through writings?
Dr. Chris Mooney
Great question. Who is actually at the councils? Usually the councils have what's called acta. Acta is Latin for the deeds. It's sort of like acts of the apostles. And the acta are just recordings of the events.
Mary McGeehan
Okay.
Dr. Chris Mooney
And often they'll mention who was present, who was present. The acta aren't always complete. We're missing the acta for some councils or there's disagreements about how reliable they are. But sometimes there's like roll call. Basically, it's the most boring part to read. But it's like, name bishop of so and so. Name bishop of place. Name bishop of place. Name bishop of place.
Mary McGeehan
Thank you. Because they're always told these people are at these councils. I'm like, how do we know that.
Dr. Chris Mooney
This was a long time ago? Sometimes you can also tell because they write letters to each other and talk about we have the letters and so, you know, we don't have like, it'd be nice to have sort of history textbooks or like a 4th century Wikipedia or something, you know, that would just. Where everybody edited their entries and said where they were. We don't have that, but we have letters as well as these kind of historical texts. Worst case scenario. There are some histories, but they're usually later. That's why I say it's a worst case scenario.
Mary McGeehan
Yes. Thank you. Well, as we're wrapping up the life of St. Gregory of Nyssa, you've mentioned a few things that he is just such a influence for us today. But for people today of pastors, how would you recommend we can look to him for intercession or guidance in summary of his great life and writings?
Dr. Chris Mooney
Great question. Maybe to sum up some of the things I've said. First, if someone wants to know more about Gregory, try reading his homilies on the Lord's Prayer. They're very good. And there's a nice introduction too to the volume that I brought up. But what are some of the things we see in Gregory? I think we see that the idea for him, contemplation of Christ was not an idle thing. You know, understanding who Christ is and the implications of the incarnation, that seeing Christ as the Son of God changes everything. It changes how we. It has to change how we relate to people. And that's one of the things that Gregory, that Gregory really saw that when we think that being a Christian makes a difference. Part of what Gregory, I think what we see from Gregory is that believing in Christ, believing who Christ is, seeing him as he really is, has to make a difference in how we relate to the world. That's maybe one thing. And I also think Gregory is a great example of someone who we might think plumbed the depths. You know, he thought about the deep things, but like the infinity of God.
Mary McGeehan
Or.
Dr. Chris Mooney
The meaning of prayer or the doctrine of the Trinity. But these are things that are actually really fruitful for us, that we can benefit from. I think Gregory's understanding of, you know, Gregory's presenting to us what it really means to believe in an infinite God who is infinitely satisfying, is crucial to the whole, to our whole way of thinking as Christians.
Mary McGeehan
Amen. Beautiful. Thank you so much for that life and reflection on St. Gregory of Nyssa. And it's a joy to learn and study with you and thank you.
Dr. Chris Mooney
It's a joy for me as well. I hope others feel the same as they get to know more about the Saints.
Mary McGeehan
Yeah, absolutely. Take so much. Just a prayer and we'll see you next time on Catholic Saints.
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Augustine Institute | Host: Mary McGeehan | Guest: Dr. Chris Mooney
Episode Date: January 10, 2026
This episode of the Catholic Saints podcast, hosted by Mary McGeehan with guest Dr. Chris Mooney, shines a spotlight on St. Gregory of Nyssa — one of the three great Cappadocian Fathers of the 4th century. The discussion delves into his unique background, theological contributions (especially on the Trinity and infinity of God), profound influence as a spiritual writer and preacher, and his revolutionary stance on issues such as slavery and the dignity of all people. The episode explores how Gregory’s life and writings can inspire contemporary Catholics and pastors.
Pastoral Relevance
On the Lord’s Prayer
On the Value of Holiness:
“She [Macrina] stood out because she was holy and because she was configured to Christ. And Gregory saw that.” — Dr. Chris Mooney (08:22)
Prayer as Intimacy:
“Prayer is intimacy with God and contemplation of the invisible. It satisfies our yearnings and makes us equal to angels.” — Gregory of Nyssa [quoted] (14:14)
Revolutionary Social Teaching:
“Gregory…is really the first witness we have in the long Christian tradition of proclaiming that slavery was an offense against God.” — Dr. Chris Mooney (05:51)
On God’s Infinity:
“God is an ocean, an infinite, endless ocean of joy.” — Dr. Chris Mooney (10:36)
On ‘Hallowed be Thy Name’:
“No good can come to us without God’s help…The most important for me is that God’s name should be glorified through my life.” — Dr. Chris Mooney paraphrasing Gregory (16:25)
On Living as a Christian:
“Believing in Christ, believing who Christ is, seeing him as he really is, has to make a difference in how we relate to the world.” — Dr. Chris Mooney (24:41)
“Gregory’s understanding of…what it really means to believe in an infinite God who is infinitely satisfying, is crucial to our whole way of thinking as Christians.” — Dr. Chris Mooney (25:48)