Expositor's Bible Commentary Commentary Galatians 3:17

"Now this I say: A covenant confirmed beforehand by God, the law, which came four hundred and thirty years after, doth not disannul, so as to make the promise of none effect." — Galatians 3:17 (ASV)

The 430 years comes from the LXX of Ex 12:40, defining the period between Abraham and Moses rather than (cf. the Hebrew text) the period during which the Israelites were slaves in Egypt. The difference is of no consequence for Paul’s argument, however, because his point depends only on the historical sequence. If God had been blessing Abraham and his posterity through the way of promise for 430 years and if he was to do the same for all humanity through Christ, how could the giving of the law annul this promise? It could not, as even the human analogy of covenants and wills shows. Therefore, the law cannot add to, nor subtract from, God’s first and only way of salvation.