Foundation Text

Galatians 4:21-31

Greek Key Terms

• G3814 παιδίσκη (paidiskē) — "slave woman" — Hagar (v. 22), representing bondage-covenant
• G1658 ἐλεύθερος (eleutheros) — "free" — Sarah (v. 22), representing freedom-covenant
• G4561 σάρξ (sarx) — "flesh" — Ishmael born "according to the flesh" (v. 23)
• G1860 ἐπαγγελία (epangelia) — "promise" — Isaac born "through the promise" (v. 23)
• G238 ἀλληγορέω (allēgoreō) — "to speak allegorically/figuratively" — "These things serve as illustrations" (v. 24) — Paul's own label for his figural (not τύπος) reading
• G1242 διαθήκη (diathēkē) — "covenant" — "the women represent two covenants" (v. 24)
• G507 ἄνω (anō) — "above" — "the Jerusalem above is free, and she is our mother" (v. 26)
• G4723 στεῖρα (steira) — "barren" — "Rejoice, O barren woman, who bears no children" (v. 27, quoting Isaiah 54:1)

Context: Paul is combating Judaizing teachers in Galatia who insist Gentile believers must be circumcised and keep the Mosaic law to belong to the covenant people. He has already argued the priority of promise over law (3:15-18), the temporary custodial role of the law (3:23-25), and the full sonship of believers in Christ (3:26-4:7). Now in 4:21-31 he delivers his climactic argument from Genesis itself. Using "allegorical" interpretation (a figural reading), he maps Hagar and Sarah onto two covenants. Hagar (slave woman, Ishmael born κατὰ σάρκα, "according to the flesh") represents the Sinai covenant, which "bears children into slavery" (v. 24) and corresponds to "the present-day Jerusalem" in bondage with her children. Sarah (free woman, Isaac born διʼ ἐπαγγελίας, "through promise") represents the new covenant and "the Jerusalem above," the mother of free-born children. Paul then quotes Isaiah 54:1 ("Rejoice, O barren woman...") to show that the promise of many children to the barren woman is fulfilled in the new covenant community. Finally, he applies Genesis 21:10 ("Expel the slave woman and her son") as Scripture's command: those who insist on law cannot be co-heirs with those who trust promise.

OT-to-OT Development

• Paul reads Genesis 16-21 (the Sarah-Hagar narrative) through Isaiah 54:1 (the barren woman who rejoices at many children)
• Isaiah himself already applies barren-mother language to exiled Zion, metaphorizing the OT pattern
• Paul combines the Genesis narrative, the Isaiah prophecy, and a command from Genesis 21:10 into a single figural argument
• Isaiah 51:2 — "Look to Abraham your father, and to Sarah who gave you birth" — also treats Sarah as paradigmatic mother of the covenant community

Connections

• TO:
  • Genesis 16 (Hagar gives birth to Ishmael)
  • Genesis 17:15-21 — Sarah's promise as covenant mother
  • Genesis 21:10 — "Expel the slave woman"
• FROM OT:
  • Isaiah 54:1 — Directly quoted (v. 27)
  • Isaiah 51:2 — Sarah as matriarch of covenant community
• FROM NT:
  • Galatians 3:29 — "if you belong to Christ, then you are Abraham's seed and heirs according to the promise"
  • Romans 9:6-9 — Not all descendants are children; children of promise are counted offspring
  • Hebrews 12:22 — "you have come to Mount Zion, to the city of the living God, the heavenly Jerusalem"
  • Revelation 21:2 — "I saw the holy city, the new Jerusalem, coming down out of heaven"

Christological Connection: Sarah's freedom is ultimately Christ's freedom. The entire figural argument hinges on Christ as the covenant mediator of the Sarah-line. Paul writes, "It is for freedom that Christ has set us free. Stand firm, then, and do not be encumbered once more by a yoke of slavery" (Galatians 5:1). This "freedom" is precisely the freedom Sarah represents — freedom from the slave-mother of law-keeping, freedom that comes through promise, freedom accessed by faith in the risen Son. Believers, "like Isaac, are children of promise" (4:28), which means they share in the free status Christ has purchased.

The "Jerusalem above" (v. 26) is the heavenly reality where Christ now reigns. Paul identifies Sarah as the mother of this heavenly city's inhabitants. Hebrews 12:22-24 makes the same move, saying believers have already come to "the heavenly Jerusalem" through Christ's mediation of "a new covenant." Revelation 21:2-10 describes the final descent of this new Jerusalem as the bride adorned for her husband — the same heavenly city Paul calls Sarah's offspring.

The Isaiah 54:1 quotation is theologically crucial. Isaiah places this call to the barren woman to rejoice immediately after the Suffering Servant's atoning work in Isaiah 53. The barren one rejoices because the Servant has accomplished what creates the many children. Paul reads this as prophetic proclamation: Christ's cross-work (the Suffering Servant's substitution) is the reason why the barren mother now has innumerable children. The church — multi-ethnic, multi-national, born through the preached gospel — is Sarah's many offspring, born only because Christ suffered and rose.

The expulsion command ("Expel the slave woman and her son") is applied by Paul not to ethnic Jews but to a covenant principle: law-bondage cannot share inheritance with promise-freedom. This is not anti-Semitic; Paul himself is a Jew, and Hagar and Ishmael were not Jewish. The point is covenantal: any attempt to add law-keeping to faith in Christ as the basis for right standing with God produces "slave children" and cannot coexist with the free inheritance Christ has won.

Paul's explicit self-description of this reading as "allegorical" (ἀλληγορούμενα) has been much debated, but functions in context as a figural reading grounded in the text's own historical realities. He is not inventing a meaning foreign to Genesis; he is showing that the Sarah-Hagar story, rightly read in light of Christ, maps the difference between the two covenants. His hermeneutic sets a pattern for reading the OT christologically: the historical narrative grounds a genuine figural correspondence to realities in Christ.

The already/not-yet framework: the freedom Sarah represents is already available to believers through Christ ("It is for freedom that Christ has set us free"); yet the heavenly Jerusalem's full descent and the consummation of the children-of-promise family await the return of Christ and the new creation (Revelation 21:2-4).

ANTI-DEFAULT CHECK: Paul labels his own move ἀλληγορούμενα (4:24) — his single NT use of the verb, deliberately not his standard τύπος vocabulary (cf. Rom 5:14; 1 Cor 10:6, 11) — and that label must be allowed to govern. The correspondence he draws is associative, not structural: two historical women stand for two covenants, two Jerusalems, two kinds of children. Typology is declined here on the escalation criterion: the new-covenant heavenly mother is equated in kind with Sarah (a free mother bearing free children) rather than escalated from her, so there is no shadow-to-substance ascent of the sort Fairbairn requires. Greidanus's own caution applies — Paul's Galatians 4 procedure cannot simply be replicated without careful qualification. Contrast is essential and structural: the entire argument runs on Hagar/Sinai/present-Jerusalem against Sarah/new-covenant/Jerusalem-above, and it is sharpened into an ecclesial boundary at 4:30 and 5:1. Not allegorical in the sense of non-historical symbol-reading — Paul's two women are real, and he reasons from their real histories. This reading matches the mirror-image classification of the same passage at TT 068 (Hagar and Ishmael).

Connection Method(s): Analogy (primary), Contrast, Promise-Fulfillment — Paul associatively identifies Sarah as the free-covenant mother whose children are those born through promise, set against Hagar/Sinai/law-bondage; the Isaiah 54:1 promise of the barren woman's many children finds fulfillment in the new covenant church born from the Suffering Servant's work.

Trajectory Table: 139 - Sarah (Mother of Promise)