Added because of transgressions, and the mediator (3:19–20)

Says Galatians 3:19 asks Τί οὖν ὁ νόμος; (Ti oun ho nomos, “Why then the law?”) and answers τῶν παραβάσεων χάριν προσετέθη (tōn parabaseōn charin prosetethē): Abbott-Smith lists the phrase under παράβασις, “transgression”, and the passive of προστίθημι, “to add, join to, give in addition”. It was added ἄχρις οὗ ἔλθῃ τὸ σπέρμα ᾧ ἐπήγγελται.

Says The law was διαταγεὶς δι’ ἀγγέλων ἐν χειρὶ μεσίτου (diatageis di’ angelōn en cheiri mesitou), “by the hand of a mediator”; the BSB has “administered through angels by a mediator”. μεσίτης is “an arbitrator, mediator”.

Says Galatians 3:20 reads ὁ δὲ μεσίτης ἑνὸς οὐκ ἔστιν, ὁ δὲ θεὸς εἷς ἐστιν (ho de mesitēs henos ouk estin ho de theos heis estin), literally “the mediator is not of one, but God is one.” The BSB, “A mediator is unnecessary, however, for only one party”, interprets the clause.

Implies The law is given a purpose and a time limit: it was added, and it runs until the seed comes.

Uncertain What “because of transgressions” means, who the mediator is, and how 3:20 argues are not settled by the grammar. No lean is taken here.