Covenants, wills, and the 430 years (3:15–17)

Says “Even a human covenant, once it is ratified, cannot be canceled or amended” (Gal 3:15; κεκυρωμένην διαθήκην; the noun is also used of a will). “The law that came 430 years later does not revoke the covenant previously established by God, so as to nullify the promise” (3:17; τετρακόσια καὶ τριάκοντα ἔτη). Exodus states, “Now the duration of the Israelites’ stay in Egypt was 430 years” (Exod 12:40).

Lightfoot notes that “in the historical statement, Exod. xii. 40 sq., it is defined more exactly as 430 years.” On counting the years from the promise to Abraham, Chrysostom writes, “four hundred and thirty years after came the Law”. Lightfoot implies the same count, calling it what appears “to have been the received chronology. It is adopted not only by St Paul here,” and adding that these matters “do not affect St Paul’s argument and cannot have entered into his thoughts.” Calvin reports the reckoning, “A promise was given to Abraham four hundred and thirty years before the publication of the law”, without making it his own. These are their readings.

Implies Because the promise was established by God first and the law came later (3:17), the later law cannot set aside or add to the earlier ratified promise, as even a human covenant cannot be amended (3:15).

Uncertain From what point the 430 years are counted, and how the figure relates to Exod 12:40, are open; this background does not fix the meaning of the text.