God has not cast away His people whom He foreknew.
Paul is speaking of God’s choice of the nation of Israel to whom He would give revelation and blessings. But this never meant that the entire nation would be saved. God always worked through a remnant as seen in the reference to Elijah.
Or do you not know what the Scripture says of Elijah, how he pleads with God against Israel, saying, “Lord, they have killed Your prophets and torn down Your altars, and I alone am left, and they seek my life”?
1 Kings 19:10
So he said, “I have been very zealous for the Lord God of hosts; for the children of Israel have forsaken Your covenant, torn down Your altars, and killed Your prophets with the sword. I alone am left; and they seek to take my life.”
PRAISE GOD FOR HIS FAITHFULNESS TO HIS WORD TO ISRAEL