What Does Galatians 3:20 Mean?

Now a mediator is not a mediator of one, but God is one. This dense, cryptic verse has sparked much debate. 'A mediator is not a mediator of one' (ho de mesitēs henos ouk estin, ὁ δὲ μεσίτης ἑνὸς οὐκ ἔστιν)—a mediator (mesitēs, μεσίτης) by definition implies two parties in negotiation or contract. Moses mediated between God and Israel at Sinai—a bilateral covenant requiring mutual obligations. Israel had to obey; God would bless. This required a mediator to broker the two-party agreement.

The contrasting statement: 'but God is one' (ho de theos heis estin, ὁ δὲ θεὸς εἷς ἐστιν). The promise (epangelia, ἐπαγγελία) to Abraham was unilateral—God alone swore the oath (Genesis 15:17, 22:16-18), requiring nothing from Abraham. No mediator was needed because the promise was God's unconditional commitment. The phrase 'God is one' could also echo the Shema (Deuteronomy 6:4)—God's unity and singularity means He acts alone in the promise-covenant, unlike the Law-covenant that required mediation between two parties.

Paul's point: the Law's bilateral, mediated nature proves its inferiority to the promise's unilateral, unmediated nature. The promise depends solely on God's faithfulness; the Law depends on human obedience—and humans fail. Therefore, the promise-gospel is superior to the Law-system. God's unilateral, gracious promise cannot be overthrown by the Law's conditional, bilateral demands.