Now I mean this. Not strictly the conclusion from Gal 3:15, Gal 3:16, since Paul does not use this phrase in drawing a conclusion (comp. 1Co 1:12, and τοῦτο δέ φημι, 1Co 7:29; 1Co 15:50). It is rather the application, for which the way was prepared in Gal 3:16, of the analogy of Gal 3:15 to the inviolable stability of God's covenant.
Four hundred and thirty years after
Bengel remarks: “The greatness of the interval increases the authority of the promise.”