Romans 11:18 - Joseph Benson’s Commentary on the Old and New Testaments

Boast not against the branches Attribute not thy being ingrafted into the good olive to thy own merits, as if thou wert worthy of the blessing. But if thou boast To humble thy pride, consider, thou bearest not the root, but the root thee The Jewish church is not ingrafted into the Gentile, but the Gentile into the Jewish; the members thereof being by faith made children of Abraham, who was constituted by God's covenant the father of all believers, receiving on their behalf the promises. The apostle's meaning is, that Abraham and his posterity derived no advantage from any covenant which God made with any of the Gentile nations: but the Gentiles have derived many benefits from the covenants which God made with Abraham and the Jews. “Because the converted Gentiles began very early to despise and hate the unbelieving Jews, on account of their opposition to the gospel, and because the apostle foresaw that in after-times the Jews would be treated with great cruelty and contempt by Christians of all denominations, he wrote this passage; in which, by mentioning the great obligations which the Gentiles are under to the Jews, he shows it to be injustice, ingratitude, and impiety, to despise and hate this people; and much more to plunder, persecute, and kill them. They were the original church and people of God. They preserved the knowledge of God when all the world was sunk in idolatry. To them we owe the Scriptures of the New Testament, as well as those of the Old; for the holy and honourable fellowship of the prophets and apostles were Jews. Of them, as concerning the flesh, Christ, the Saviour of the world, came. All the knowledge of religion, therefore, which we enjoy, is derived from them. And surely something of kindness and gratitude is due for such obligations.” Macknight.