Catholic Bible Study: Galatians 4:21-31

Podcast: Augustine Institute
Hosts: Dr. Michael Barber and Dr. Jim Prothero
Date: October 23, 2025

Episode Overview

In this episode, Dr. Michael Barber and Dr. Jim Prothero delve into Galatians 4:21-31, focusing on St. Paul’s allegorical comparison of Hagar and Sarah and what this means for Christians navigating Old Covenant law and New Covenant faith. The discussion centers on the entanglement of law, grace, works of the flesh, and the promise of the Spirit, drawing deep connections between the Genesis narrative and Paul’s argument to the Galatians. The hosts break down the implications for Christian identity, faith, and daily living, highlighting how these ancient texts address perennial human temptation to "help God" rather than trust in His promises.

Key Discussion Points & Insights

1. Background: Abraham, Hagar, and Sarah

[00:00–04:21]

• Dr. Prothero recaps the Genesis story: God’s promise to Abraham for a great family (Genesis 12, 15), Sarah’s doubt, and her suggestion to Abraham to have a child with her handmaid Hagar, leading to Ishmael’s birth (00:42).
• Abraham’s attempt is explained as a human effort to fulfill divine promise by his own means:
  “I've always thought that...Abraham taking the Benjamin Franklin approach. Well, God helps those who help themselves, right?” – Dr. Barber (01:39)

2. Promise vs. Flesh: The Two Sons as Allegory

[04:21–08:52]

• Paul calls Isaac, son of Sarah, the “child of promise,” born through God’s supernatural intervention, while Ishmael, son of Hagar, is “born according to the flesh”—the result of human initiative.
• Paul interprets these mothers as representing two covenants: Hagar (the Old Covenant, Mount Sinai, slavery) and Sarah (the New Covenant, Jerusalem above, freedom).
• “Now this situation of the two women and their children, this may be interpreted allegorically. So symbolically, these women are two covenants.” – Dr. Barber quoting Paul (04:44)

3. Slavery and Freedom: Legalism vs. Promise

[08:52–11:11]

• Paul relates Hagar and Ishmael to “the present Jerusalem” and life under the Mosaic Law, while Sarah and Isaac embody liberty in the Spirit.
• The crux: Christians must claim identity as “children of the promise”—born from faith, not works (09:31).
• “God promised Abraham, you will have a child...and through that family...Jesus Christ, blessing for the whole world.” – Dr. Prothero (09:31)

4. Application: Temptation to Trust in the Flesh

[11:11–17:25]

• Galatian Christians face pressure from those urging circumcision as entry into God’s family—making them spiritual descendants of Hagar, “slaves” not “free.”
• The Old and New Covenants are contrasted:
  • Old: Hagar, Ishmael, Sinai, present Jerusalem, law, slavery, born according to flesh.
  • New: Sarah, Isaac, heavenly Jerusalem, Spirit, freedom, promise (11:20).
• “If you insist on being circumcised, what you’re doing is...putting your faith in the flesh, quite literally, right?...What ultimately matters is not what you do with your flesh, but what happens in the Spirit.” – Dr. Barber (12:19)

5. Paul’s View of the Law: Not Bad, But Fulfilled

[14:02–17:25]

• Paul is not anti-Law. He insists the Law was good and preparatory for Christ, but “a code of text doesn’t save anybody. It’s God who saves.” (14:14)
• Once Christ arrives, relationship with God rests on spiritual rebirth, not on compliance with legal rituals.
• “Is the law opposed to God’s promises? ...No, it’s not. God gave the law on purpose for a good reason. But now that the Son has come...it’s the Son to whom we look for our relationship with God...” – Dr. Prothero (15:00)

6. Personal & Practical Implications

[17:25–23:54]

• Abraham’s struggle parallels ours: the temptation to “help God out” and act as if everything depends on our effort versus trusting the Spirit.
• “So much of my life...I feel like, okay, I got to make this happen. ...If I succeed, it’s ultimately because of the Spirit.” – Dr. Barber (18:03)
• The urge to place confidence in external markers—circumcision then, baptismal certificates or rituals now—is criticized as a shallow substitute for real transformation.

7. Faith vs. Despair: Letting God Love Us

[23:54–25:31]

• Emphasis on “faith” means receiving God’s love and depending on Him in the midst of weakness, not only trusting in exceptional performance.
• “Faith is the openness to God’s love and being ready to seek God, both in trusting Him instead of ourselves when we're confident and trusting Him...when we're despairing.” – Dr. Prothero (24:23)

8. ‘Cast Out the Slave Woman’: Rejecting Legalism

[25:31–26:38]

• Paul’s use of “cast out the slave woman” is invoked to urge the Galatians to reject the influence of those pushing law observance as necessary for salvation.
• Practically, believers must “run [false teachers] out of town” and also “cast out this kind of thinking from their hearts.” (25:59–26:38)

9. Circumcision, the Flesh, and Spirituality

[26:38–30:21]

• Paul connects circumcision to “the flesh”—not just bodily, but representative of all human striving and passions apart from God.
• Even good rituals risk becoming spiritual shortcuts or symbols of superiority if they’re detached from authentic spiritual renewal.
• “Things that are meant to teach us to repent...can somehow be distorted...to sort of be a kind of spiritual, like, unholy talisman.” – Dr. Barber (28:22)

10. Integration of Body and Spirit

[29:22–30:22]

• Paul’s concept of “flesh vs. spirit” isn’t anti-body; the faith is bodily and spiritual (baptism, Eucharist, resurrection).
• The real issue is letting bodily observances serve the Spirit, not replace it.

Notable Quotes & Memorable Moments

• Dr. Barber:
  “I've always thought that...Abraham taking the Benjamin Franklin approach. Well, God helps those who help themselves, right?” (01:39)

• Dr. Prothero:
  “Are you going to follow Jesus or are you going to run over to the law? ...Once Christ arrives, it's the Son to whom we look for our relationship with God...” (15:00)

• Dr. Barber:
  “What ultimately matters is not what you do with your flesh, but what happens in the Spirit.” (12:19)

• Dr. Prothero:
  “Faith is the openness to God’s love and being ready to seek God, both in...confidence and...when we're despairing.” (24:23)

• Dr. Barber:
  “We can fall into the same trap that the Galatians are tempted with...you don't need to do that, because now all Gentiles can be [included]...” (18:50)

• Dr. Prothero:
  “A code of text doesn’t save anybody. It’s God who saves.” (14:14)

Key Timestamps

• 00:00 – 04:21: Introduction and Genesis background of Abraham, Sarah, and Hagar
• 04:21 – 08:52: Allegorical meaning: two sons, two covenants
• 08:52 – 11:11: Children of the promise—Christian identity in Christ
• 11:11 – 14:02: Law, legalism, and contrasting covenants
• 14:02 – 17:25: Paul's view of the Mosaic Law post-Christ
• 17:25 – 23:54: Practical dependency on the Spirit vs. self-effort
• 23:54 – 25:31: How to let God’s promise and love define us, avoiding despair
• 25:31 – 26:38: Meaning of “cast out the slave woman” for Galatians and today
• 26:38 – 30:21: Circumcision as “flesh”, spiritual pitfalls of ritualism
• 29:22 – 30:22: Embodied faith: reconciling body and spirit in Christian practice

Conclusion

This episode provides an in-depth, pastorally sensitive, and richly theological exploration of Galatians 4:21-31. Barber and Prothero guide listeners through the dense symbolism of Paul, the scriptural context, and the everyday implications for Christian discipleship. Throughout, they underscore that trust in God’s promise, openness to His Spirit, and rejecting reliance on external markers define the New Covenant life. The call for listeners is both intellectual and practical: to study deeply, but more importantly, to trust in the Spirit’s transformative power more than in their own efforts.