John Calvin Commentary Romans 11:28

"As touching the gospel, they are enemies for your sake: but as touching the election, they are beloved for the fathers` sake." — Romans 11:28 (ASV)

With regard indeed to the gospel, etc. He shows that the worst thing in the Jews should not subject them to the contempt of the Gentiles. Their chief crime was unbelief: but Paul teaches us that they were thus blinded for a time by God’s providence, so that a way to the gospel could be opened for the Gentiles, and that they were still not forever excluded from the favor of God.

He then admits that at present they were alienated from God on account of the gospel, so that the salvation, which at first was deposited with them, could come to the Gentiles; yet God was not unmindful of the covenant which he had made with their fathers, and by which he testified that according to his eternal purpose he loved that nation. This he confirms by this remarkable declaration—that the grace of the divine calling cannot be made void; for this is the import of the words—