Galatians 3:20 Commentary: The Mediator and the One God

The backdrop of this verse is the dramatic scene at Mount Sinai. When God gave the law, He did so through angels and a mediator, Moses (Galatians 3:19). The people were terrified and begged Moses to speak instead of God directly (Exodus 20:19). In contrast, God dealt with Abraham personally: He appeared, made a covenant with signs like a smoking fire pot (Genesis 15), and changed his name (Genesis 17). Paul is contrasting two kinds of divine dealings.

The Shema (Deuteronomy 6:4) proclaimed “Yahweh is one”, an affirmation not just of monotheism but of God’s self-consistency. If God is one, He does not change His mind about salvation. The law was a temporary addition “because of transgressions” (Galatians 3:19), until the Seed (Christ) should come. The mediator Moses stood between a holy God and a sinful people, highlighting distance. But the promise comes directly from the one God who is the God of both Jews and Gentiles (Romans 3:29-30).

The Jewish context also includes the tradition that the law was mediated by angels (Acts 7:53; Hebrews 2:2). Paul’s argument hinges on the fact that a mediated covenant implies two parties at a distance. But God’s promise to Abraham was a one-party covenant: God made it with Himself, as the smoking oven and flaming torch passed between the pieces alone (Genesis 15:17). This unilateral character shows that salvation rests on God’s faithfulness, not human conditions. The law, by contrast, required obedience and came with curses (Deuteronomy 27:26). So Paul uses the logic of “mediator implies two; God is one” to show that the law was a temporary departure from God’s normal mode of dealing, direct promise. When we encounter this verse, we are invited to trust a God who does not change and keeps covenant.

No significant textual variants are noted in the sources consulted for this verse. The reading is stable across the Greek manuscript tradition. The only minor variation is the presence or absence of the article before “God” in some late manuscripts, but it does not affect the meaning.

Galatians 3:20 has long been considered one of the most challenging verses in the New Testament. The Cambridge Bible notes the claim that it “has received 430 interpretations.” From the early church onward, interpreters differed on whether the mediator in view was Moses or Christ. The sixteenth-century reformer John Calvin took the mediator as Christ, though he acknowledged the more common reading as Moses. The Cambridge Bible for Schools and Colleges (1880) summarizes the history of interpretation, and J.B. Lightfoot helped clarify the grammar, arguing that the generic article and the Shema quotation settle the meaning: the law’s mediated nature contrasts with God’s direct promise. Modern scholarship continues to debate its exact function in Paul’s argument, but most agree it underscores the superiority of the Abrahamic covenant over the Mosaic law.

Three-point outline

1. The law required a mediator, The very presence of a mediator (Moses) shows distance, demand, and a bilateral contract. The people were kept at arm’s length (Exodus 19:12).
2. The promise came directly, God dealt with Abraham face-to-face, without intermediaries. This signals grace and intimacy.
3. God is one, He does not change. His promise is consistent across all peoples and times, bringing Jew and Gentile into the same blessing.

Five-point outline

1. Proclamation: God gave a direct promise to Abraham.
2. Problem: The law, given through a mediator, seems to compete with the promise.
3. Principle: A mediator implies two parties; but God is one and acts on His own.
4. Purpose: The law was added temporarily, not to provide life but to expose sin and drive us to Christ (Galatians 3:24).
5. Unity: The one God unites all believers, Jew, Gentile, slave, free, male, female, in one promise (vv. 26, 29).

Illustration hooks

• A parent writing a birthday card to a child vs. a legal contract drawn up by a lawyer. The card expresses love directly; the contract requires signatures, witnesses, and conditions. The promise is a card; the law is a contract.
• An email that goes through three forwarding addresses before reaching you vs. a direct, face-to-face conversation. The direct conversation carries more intimacy and certainty. The mediated law keeps us at a distance; the promise brings us near.
• A will vs. a lease. A will is a one-party gift that takes effect when the testator dies. A lease is a contract that both landlord and tenant must fulfill. Paul says the promise is like a will, not a lease.

Questions your congregation is asking

• If God gives His promise directly, why does the law still feel necessary for our daily walk with Him?
• How can Paul say there is “no mediator” in the promise when Jesus Christ is the mediator of the new covenant (1 Timothy 2:5)?
• What does it mean for us practically that we come to God based on a unilateral promise, not on our performance of a contract?

This brief, puzzling verse sits at the heart of Paul’s argument about law and promise. Before you discuss it, read Galatians 3:15-22 to see the context.

Discussion questions

1. What does Paul mean by “mediator” in this passage? Who is he referring to, and why?
2. Why does a mediator by definition imply two parties? How does that affect the way we understand the law?
3. How does the phrase “God is one” (echoing Deuteronomy 6:4) contrast with the concept of a mediator?
4. How does the law’s mediated nature compare to Abraham’s direct experience with God? Which one is more like your usual sense of approaching God?
5. What difference does it make for your relationship with God that His promise is unilateral, not a contract that you can break?
6. How does this verse help us understand the temporary purpose of the law? Why did God give it if the promise was always enough?
7. How does Christ’s mediation differ from Moses’? In what ways is Jesus a mediator who unites rather than separates (Ephesians 2:14-18)?