But I say, Did not Israel know? First Moses saith, I will provoke you to jealousy by them that are no people, and by a foolish nation I will anger you.
But I say, Did not Israel know? - that is, from their own Scriptures, of God's intention to bring in the Gentiles?
First, Moses saith - or, 'was the first (in the prophetic line) to say,'
I will provoke you to jealousy by [them that are] no people, х ep' (G1909) ouk (G3756) ethnei (G1484)] - not 'against' (as the Vulgate), nor 'by' (as Beza and our version), but 'on account of a no-nation' [see Fritzsche on the force of epi (G1909) here].
[And] by a foolish nation ('on account of a nation without understanding,') will I anger you. The words are from Deuteronomy 32:21, (almost entirely as in the Septuagint) In that chapter Moses prophetically sings the future destinies of his people; and in this verse God warns His ancient people that, because they had moved Him (that is, because in after-times they would move Him) to jealousy with their "no gods," and provoked Him to anger with their vanities, He, in requital, would move them to jealousy by receiving into His favour a no-nation, and provoke them to anger by adopting a nation void of understanding.