After all Paul has said about Israel's unbelief, a reader might conclude that God was finished with His people. Paul names that conclusion so he can deny it. Gill says Paul saw that his quotations from Moses and Isaiah would raise an objection, which he "here takes up from the mouth of an adversary." Barnes explains that Paul wants to show he did not mean all Jews must be cast off, so "he adduces his own case." The question guards against a wrong reading of Romans 10.

Paul answers with his strongest denial: "God forbid" (Romans 11:1). His first proof is himself: "For I also am an Israelite." Then he states it plainly: "God hath not cast away his people which he foreknew" (Romans 11:2). He goes on to Elijah's day, when God kept seven thousand faithful (Romans 11:2-4), and concludes, "Even so then at this present time also there is a remnant according to the election of grace" (Romans 11:5).

"God forbid" translates the Greek mē genoito, "may it not be." Barnes says, "Literally, it may not or cannot be." Paul names his tribe, Benjamin, as he also does in Philippians 3:5. Barnes says, "The apostle mentions this to show that he was a Jew in every respect." Matthew Henry notes that "Paul was a chosen vessel" (Acts 9:15), and yet he was of the seed of Abraham.

This question is about God's faithfulness. If God had cast away His people, His promises would be in doubt. Paul answers that God has not, and the reason lies in God Himself: these are the people "which he foreknew" (Romans 11:2). Later Paul adds that "the gifts and calling of God are without repentance" (Romans 11:29).

Paul's own life is the first evidence. He had once "persecuted the church of God," yet God "called me by his grace" (Galatians 1:13, 15). If God could save Paul, He had not given up on Israel. The chapter ends not in rejection but in praise for "the depth of the riches both of the wisdom and knowledge of God" (Romans 11:33).