
In this episode we consider the Bible's instructions about sexual immorality.
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Back to the Bible. Let it be our plea. God's word alone, our authority, every word, every step in the name of Christ. Back to the Bible for the way of life.
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Welcome to this period of Bible study. My name is Larson Plyler and this is the Back to the Bible radio program and podcast. We are delighted to have the opportunity to share with you in a consideration of God's Word. Today I'm going to take our study mostly from the book of First Thessalonians, chapter four. And so you might turn over there if you have a Bible handy. We'll make reference to other passages, but that will provide the basic context and outline for our study today. Let me make mention of a few things so that you can check these things out if you would like. The first thing is you can always go to our website, backtothebiblepodcast.com there you can find information about this program. You can find ways to contact us, to reach out, to ask questions or to make comments on the lessons that you hear. We are always happy to hear from people who are listening and whether or not they agree with the program. We're happy to take questions and respond to things that you have to say about the program and perhaps it would provide a lesson for us down the road. Let me also say that if you're looking for a congregation nearby that you could assemble with that is concerned with going back to the Bible, now let me put a condition on it, as I've done before. I can guarantee that there will not be any perfect congregations that I recommend to you because every congregation is made up of imperfect people. But I believe that I can point you in the direction of congregations that are trying to go back to the Bible for what they teach and for what they practice and for how the members live in their day to day lives. And so if you can, if you want to reach out, you are welcome to, and I'll try to put you in contact with a congregation or with somebody nearby who would be ready to study with you and look forward to that opportunity. Let me also mention I have written a book and I am thankful to have had the opportunity to do that. And I am so thankful for the response that many people have given to it. It's called Anchors in a Sea of Questions. And the idea behind the book is to provide clear and foundational truths that will help us when there are questions that we are struggling with or maybe that we can't even find the answer to. And in my mind, I think about it for young folks, but also for People who are interested in helping young folks or who are struggling with the questions themselves about God and about the Bible and about truth and all of those things. So that when the time comes and that there are questions that these people have that we can ensure that even if we can't find the precise answer that satisfies their question, we can help them to rest on the truth. That there is a God, that Jesus was raised from the dead, that the Bible is reliable and trustworthy, and that there is a way for us to do God's will. And there are answers to lots of our questions. And as we set those anchors. And so you can access that from the website and it's called Anchors in a Sea of Questions. And there's a tab at the top of the website backtothebiblepodcast.com there's a tab there called Extras. And in that extras there's a link to the anchors book. You can also just go straight to the CEI Bookstore in Athens, Alabama. You can go to their website, it's truthbooks.com and you can search for it there and it would be available. Well, thank you for indulging me in that and would love for you to check that out as you have opportunity. So let's come to first Thessalonians, chapter four. And the reason that I want to come to that text today is because of what it has to say about sexual immorality. Sexual immorality. First Thessalonians, chapter 4, beginning at verse 1. The text there, Paul says, finally, brothers, we ask and exhort you in the Lord Jesus that as you receive from us as to how you ought to walk and please God just as you actually do walk, that you excel still more. For you know what commandments we gave you through the Lord Jesus, for this is the will of God. Your that you abstain from sexual immorality, that each of you know how to possess his own vessel in sanctification and honor, not in lustful passion like the Gentiles who do not know God and that no man transgress and defraud his brother in the matter. Because the Lord is the avenger in all things. Just as we also told you before and solemnly warned you, for God did not call us to impurity, but in sanctification. Consequently, he who sets this aside is not setting aside man, but the God who gives his Holy Spirit to you. Now, the Scriptures have so much to say about the subject of sexual immorality. I don't know that there is a book of the New Testament that does not in some way along the way address sexual immorality. Maybe you could point to a few exceptions, some of those shorter epistles, Philemon, second and third John, maybe they don't reference it. But so many of the books of the New Testament reference the danger of sexual immorality. Now this is a subject for everyone to listen to. Now, you might say that, do I really need to be preaching about this? Do I really need to be teaching about this? And let me say that everybody needs to hear it. I want you to think about the letter in which this is written in First Thessalonians, chapter 4. Because in First Thessalonians, Chapter 1 and verse 2, he says to them, he says, in verse 2 of 1 Thessalonians 1, we give thanks to God always for you, making mention of you in our prayers, remembering you without cease your work of faith, your labor of love, and your steadfastness of hope in our Lord Jesus Christ before God and Father. So I want you to think about that. These people Paul is thankful for, he is encouraged by their work of faith, their labor of love, and their steadfastness of hope. Back in chapter four that we just read, he said that you walk and please God just as you also do, that they excel still more that they knew the commandments that they gave through the Lord Jesus. So these people were not ignorant of the instructions and they were obeying God. And yet Paul still gives instructions about the need to abstain from sexual immorality. It does not seem to me that there is a level of spiritual maturity where this does not at least need to be considered along the way because of the great danger that it is to us and the people who are around us. Also think About Deuteronomy, chapter 31, verses 10 through 13. Someone might say, well, why would we talk about this where there might be little ones listening, There might be children who are paying attention. When we think About Deuteronomy, chapter 31, Moses said that every seven years, at the time of the feast of booths or the feast of tabernacles, they were to gather everyone together and they were to read the law, all of the law. And everybody was together, men, women, little children, even the sojourner and the stranger that was among them, to hear all the law read so that they would learn to fear God. Now just imagine all of the law of Moses being read to those little children. Do you think they're learning anything about the danger of sexual immorality from the reading of the law? Do you think they're reading anything or hearing anything about that. In fact, they are. And let me say this, that with our children, with our young people, there are conversations that we need to have, because the conversations are happening whether we have them with them or not. That is, the world is promoting sexual immorality all around us. And if we're not very careful, not only is the conversation not happening from a scriptural point of view, but the conversation is happening from a devilish point of view. And so either we completely insulate them, which doesn't make it better, because they're still going to need these instructions at some point, but either we completely insulate them, but recognizing that that's almost impossible to do, we need to have conversations along the way about sexual immorality and fornication. Now, when we come to this word fornication or sexual immorality, let me take you to Hebrews chapter 13 and verse 4. And there the Hebrew writer says, marriage is to be held in honor among all, and the marriage bed is to be undefiled for the sexually immoral and adulterers. God will judge. When we think about fornication, I think it is helpful to look at Hebrews 13:4 and say that there is a sexual relationship between husband and wife that is perfectly appropriate and good, that the marriage is honorable, the marriage bed undefiled. And when we think about fornication, we are talking about sexual engagement outside of the union between husband and wife. And that's in any situation except for a husband and a wife. Engagement outside of that qualifies as fornication. Now, you might also, from time to time in this passage, for example, see adulterers, and adulterers is when one of those people, at least one of them, is already committed to another person in marriage. So fornication would be a broader term that would include all of the engagements. And adultery would be a term that would include when one person is already committed in a marriage to someone else. Now, I think we need to go to Leviticus 18. Now, we're not going to be reading all of Leviticus 18, but I want you to go through that text. If you have opportunity, you can look at it now if you would like. And as you read through Leviticus 18, you will see there are all sorts of different descriptions of illicit, abominating sexual engagements in Leviticus 18. Now, how do we know that that, and I believe it is in fact what Jesus and the apostles, when they reference fornication, I believe that is in fact what they were doing, what they were referencing. And what I mean is that when Jesus teaches in the New Testament that fornication is a sin in the book of Matthew, Whether it's Matthew 19 or Mark chapter 7 or another text, I know that that's what Jesus was meaning by fornication, because he was getting his definition for biblical terms from the Old Testament. He was not making up many terms as he went. He was referencing the scriptures that he had, especially when it comes to fornication. Now, in Acts 15, I think we have an even more direct reference to Luke 18. In Acts 15, these Judaizing teachers had come to the church at Antioch, at least as we begin this chapter, saying that it was necessary for Gentiles to be circumcised and to follow the law. If they were going to be saved, it was necessary that they do so. And what Paul and Barnabas do is they go to Jerusalem to address this issue. Now, I think we should consider that the meeting at the church at Jerusalem is not going to be a church vote on what the policy is going to be, and there will be a debate. But what's going to happen definitively is that the apostles are going to be the ones who declare what the truth is and that Jesus, brother James, is going to be the one. I believe he is one of the elders at the church that there. And he will be one who will say, let's send out a letter with regards to this. Now, I want you to look at the conclusion that they come to in Acts chapter 15 and in verse 19, this is James words, he says, therefore I judge that we do not trouble those who are turning to God from among the Gentiles, but that we write to them that they abstain from things contaminated by idols and from sexual immorality and from what is strangled and from blood. For from ancient generations Moses has those who preach him in every city, since he is read in the synagogues and every Sabbath. And then if you'll drop down in the letter he says in verse 28, for it seemed good to the Holy Spirit and to us to lay upon you no greater burden than these, that you abstain from things sacrificed to idols, and from blood and from things strangled and from sexual immorality, from which, if you keep yourselves, you will do well. Now, when you read that, you say, well, are those all the rules for Gentiles? Well, no. Every letter has instructions and rules and demands for people, all nations. But what's happening here is in Acts 15 the apostles have concluded, of course, that the old law was not binding on Gentiles. They didn't need to be circumcised. They didn't need to distinguish between clean and unclean meats. They didn't need to keep the Sabbath in the way they did in the Old Testament. All of those things have passed away. And yet here's what's happening. They are referencing Leviticus 17 and 18. If you'll look at these things that are referenced here. Sacrifice to idols, blood, things strangled, and sexual immorality. Those things are the topics of Leviticus 17, 18. That is what they're referring to there. Now, how do I know that the things in Leviticus 17 and 18 were intended for more people than just the Jewish people? It says at the end of chapter 18, after talking about all of that sexual immorality, Moses says that it's because of these things that God is bringing judgment on the nations that were in Canaan and that the land was vomiting them out because of their participation in these activities. So what's happening in Acts 15 is that the apostles are saying, you are not bound by the old law. You are not bound by the law of Moses. There's no need to circumcise yourselves in order to become Jews before you can become Christians. That's the basic principle. However, there are some things recorded in the old law that were not just for the Jews, but that God held people accountable to of all time. And one of those passages is Leviticus 17:18, where you would have things sacrificed to idols, things that are strangled from blood and from sexual immorality. And what the apostles see in that and what the Bible students in Acts 15 see in that is that God had always held Gentiles accountable for those things. That was not something they could disregard. So they say Moses is read in the synagogue every Sabbath. They're gonna say, wait a second, isn't that stuff about sexual immorality? Isn't that stuff about things sacrificed to idols? Isn't that stuff about blood? Isn't that all in the Old Testament? I guess we don't have to worry about that anymore. Whoa, whoa, whoa, whoa. No, no, no, no. That's included in what Moses had to say, but it was always intended for the Gentiles, which we can see at the end of Leviticus 18. Now, all that is to say is this, that when they are defining sexual immorality, that is the passage that they're referencing. So if you read through what's happening in that text, I think you'll get a very clear understanding, maybe a more clear understanding than you thought you needed of what's involved in Fornication. And it involves all sorts of things that we need to be very aware of. Let me also mention to you how Paul describes it in First Corinthians, chapter 6, verses 9 through 11. In First Corinthians 6, 9, 11, he says, do you not know that the unrighteous will not inherit the kingdom of God? He says there in the middle of verse nine, do not be deceived. Neither the sexually immoral, that's our word. Fornicators, nor idolaters, nor adulterers, nor effeminate, nor homosexuals, nor thieves, nor the greedy, nor drunkards, nor revilers, nor swindlers will inherit the kingdom of God. And such were some of you. But you were washed, you were sanctified, you were justified in the name of the Lord Jesus and in the spirit of our God. That idea there, that you have several things mentioned here that we need to be aware of. You have fornicators, you have adulterers, you have effeminate and homosexuals. And that has to do with homosexuality, but it has to do with two different sides of that. And you can do some reading on that and find out what the text there means. But what we have there is special definitions for understanding what is violating God's law of marriage. Now let me say this. The word, the Greek word behind fornication is the word porneia. Now, when we see that word, it's very likely that you see in that a root word for a word we use pretty regularly to talk about illicit images of people. Porneia is the word for fornication. And what we have done is we have taken that word. The Greeks and the Romans took that word and they created the word pornography, graphi, meaning writing or drawing. And there are writings and there are images about fornication occurring. And we know those are illicit images called pornography. Now, where do those images come in? Well, let me say this. Just because we get the word for those images from the same root word doesn't mean that that's what Paul is talking about when he talks about fornication. I need that to make sense, because sometimes people suggest that pornography is an acceptable condition for divorce because of what Jesus says in Matthew, chapter five, that whoever looks at a woman to lust after her has committed adultery with her in his heart. And what they say is, well, if they've committed adultery in their heart, then that is a justification for. For divorce. Because adultery is the only viable connection or the only viable condition, I should say, for divorce. That's right. Adultery is the only viable condition for divorce. However, When Jesus says in Matthew, chapter 5, verses 27 through 30, that when someone looks at a woman to lust for he's already committed adultery with her in his heart, then he is not saying that that is a condition for divorce. Because even though that man has sinned, even though he has transgressed against God, the conclusion of that in the consequences of that are not the same. Can I give you an example? Think about Matthew, chapter 5, verses 21 through 24, where he talks about someone who hates his brother. It's as if he is guilty of murder. Now, does that man, we put him in the electric chair because he hates his brother? No. And Jesus would not recommend that either. But rather we say, this man already is thinking in line with what would actually cause him to commit the sin outwardly as well. And Jesus is trying to address the heart of the matter. He is addressing the heart of the matter. So let me say this, that pornography is absolutely a sin. It is absolutely an abomination before God. It is a transgression of the will of Jesus Christ. And if we are inclined to that, if we are drawn by that, Jesus says, it's better to pluck out an eye or cut off a hand. Now, I know that you might say, well, if I pluck out one eye, don't I have the other one to lust with too? That's right. So I think Jesus is being hyperbolic here and saying that there is no sacrifice. There's no reason we shouldn't be willing to get rid of anything that would keep us. That would keep us safe from engaging in such activities. And. And we need to be willing to do that. But in verse 32, he says, I say to you that everyone who divorces his wife, except for the cause of fornication, makes her to commit adultery. And whoever marries a divorced woman commits adultery. And so what we see here is that the images are certainly significant. They are certainly inclining someone to committing that sort of act. And in God's eyes, they have committed adultery in their heart, but they haven't committed adultery in the actual terms of fornication and adultery. And so it does not serve as a justification for divorce. But I want you going back to 1st Thessalonians 4 as we draw to a close for today's session. And we will pick this up, Lord willing, at some point down the road. But I want you to consider the weight that Paul puts on this teaching about sexual immorality here in 1st Thessalonians. In 1 Thessalonians, chapter 4. Look at this. He says, finally then brothers, we ask you and exhort you in the name of the Lord Jesus, that just as you receive from us how you ought to walk and please God, that just as you actually do walk, that you excel still more. Going back to verses 11 through 13, he says, may our God and Father himself, Jesus our Lord, direct our way to you. And may the Lord cause you to increase and abound in love for one another and for all people, just as we do for you, so that he may strengthen your hearts blameless in holiness before our God and Father at the coming of our Lord Jesus Christ with all his saints. So he says, God wants to make you holy. We're praying that he will make you holy. And he says for verse three. This is the will of God, your sanctification, that you abstain from sexual immorality. Look at verse 5. Not in lustful passion like the Gentiles who do not know God. Verse 6. He says that the Lord is the avenger in all these things. Verse 7. For God did not call us to impurity, but sanctification. And then look at verse 8. Whoever sets this aside is not setting aside the man who told you, but God who gives His Holy Spirit to you. God's will for you is holiness. Verse 8. Therefore whoever sets this aside is not setting aside man, but the God who gives His Holy Spirit to you. Now is this against man? Yes, it is. Look at verse six. He says that no man transgress and defraud his brother in the name because of the Lord in the matter, because the Lord is the avenger of all these things. Just as we told you before and solemnly warned you. Yes, this is against man, but it's not against man's rule. Right, it's against God's rules. Sometimes people suggest that the issue here is just because we are violating other people and we are violating other people. But it's deeper than that. We are violating God's instructions. It's not just against man's made up rules. It's not just against man's made up traditions. It's against the will of God. From the very beginning. I want you to consider the weight God places on this sin. We know that God hates divorce. Malachi, chapter 2, verse 16. But he allowed only one exception. One condition upon which somebody could divorce their spouse and that was the cause of fornication. Matthew 19:9. So God hates divorce, but but for this one thing he would allow divorce. That's how much he hates this. I want you to notice through this text that God's will focuses on abstinence from sexual immorality. That his will is for holiness and purity. And not. And not for impurity, but for sanctification. Because God's will is that one man and one woman in marriage and in the undefiled bed. That that is where they find that connection. Until next time. We bid you a pleasant good day.
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Back to the Bible. Let it be our plea. God's word alone, our authority. Every word, every step, every in the name of Christ. Back to the Bible for the way of life.
Host: Larsen Plyler
Episode 129: Sexual Immorality
Date: October 26, 2025
In this episode, Larsen Plyler provides a thorough Bible-based examination of sexual immorality, focusing primarily on 1 Thessalonians 4. Through textual analysis, historical context, and cross-referencing, Plyler addresses what scripture teaches regarding sexual conduct, how believers should understand and guard against sexual immorality, and why these teachings are relevant for all, regardless of age or spiritual maturity.
(Starts at 04:54)
“The world is promoting sexual immorality all around us. …the conversation is happening from a devilish point of view. And so either we completely insulate them, which doesn’t make it better... or we need to have conversations along the way about sexual immorality.” (11:45)
(Hebrews 13:4, Leviticus 18; starts at 14:42)
Fornication broadly refers to sexual activity outside the marriage between a husband and wife.
Adultery is a subset, describing sexual activity where at least one party is already married to someone else.
Fornication encompasses a variety of illicit acts detailed in Leviticus 18, which Jesus and the apostles referenced as authoritative:
“When we think about fornication, we are talking about sexual engagement outside of the union between husband and wife… Engagement outside of that qualifies as fornication.” (13:30)
(Acts 15, Leviticus 17-18; starts at 16:30)
Early church debates (Acts 15) clarified that while many aspects of the Mosaic Law were not binding on Gentile Christians, certain universal moral standards, including prohibitions from Leviticus 17-18 (idolatry, blood, strangled things, and sexual immorality) still applied.
These prohibitions were not only for Jews—God judged the pagan nations for these same sins (Leviticus 18:24-28).
“There are some things recorded in the old law that were not just for the Jews… that God held people accountable to of all time, and one of those passages is Leviticus 17-18.” (19:55)
(1 Corinthians 6, 1 Thessalonians 4; starts at 23:41)
1 Corinthians 6:9-11 lists fornication, adultery, homosexuality, and other sins as disqualifying from inheritance in the kingdom of God.
Paul stresses the need for Christians to “possess his own vessel in sanctification and honor, not in lustful passion like the Gentiles who do not know God.” (1 Thess. 4:4-5)
“Such were some of you. But you were washed, you were sanctified, you were justified in the name of the Lord Jesus.” (26:27)
(Clarifying modern application; starts at 25:00)
The Greek word ‘porneia’ (fornication) is the root for ‘pornography.’
Viewing pornography is a sin, but Plyler clarifies that, biblically, it does not meet the scriptural definition of adultery in the physical/legal sense and therefore does not provide scriptural cause for divorce.
Jesus’ teachings in Matthew 5 address the inward heart issues—lustful looking is a sin, but it is not equated by Jesus with the act of adultery regarding divorce.
“Pornography is absolutely a sin. It is absolutely an abomination before God. …But they haven’t committed adultery in the actual terms of fornication and adultery.” (27:50)
(Returns to 1 Thess. 4; starts at 29:13)
God calls believers to sanctification and holiness as His will for their lives.
Violating sexual morality is an offense not just against human tradition but directly against God:
“Whoever sets this aside is not setting aside the man who told you, but God who gives His Holy Spirit to you.” (31:17)
God’s standard for marriage is strict—divorce is hated by God and only permitted in the case of fornication (Malachi 2:16, Matthew 19:9).
“That’s how much [God] hates this. …God’s will focuses on abstinence from sexual immorality. His will is for holiness and purity.” (33:51)
On teaching children:
“There are conversations that we need to have, because the conversations are happening whether we have them with them or not.” (11:53)
On defining sin and consequence:
“Jesus is trying to address the heart of the matter. …Just because we get the word [pornography] from the same root doesn’t mean that’s what Paul is talking about when he talks about fornication.” (27:44)
On the seriousness of sexual sin:
“It’s not just against man’s made up rules. …We are violating God’s instructions. It’s not just against man’s made up traditions. It’s against the will of God from the very beginning.” (32:45)
Larsen Plyler’s teaching in this episode underscores that sexual immorality is a profoundly serious matter with implications for every believer. By grounding the discussion in biblical text, he clarifies the definitions, warnings, and the weight God places on sexual purity, calling listeners to personal holiness above all and reminding them that God’s standard—not societal norms—must be the guide for life and doctrine.