Romans 11:28 As concerning the gospel, they are enemies for your sakes: but as touching the election, they are beloved for the fathers' sakes.
29 For the gifts and calling of God are without repentance ...
Why are these such important verses? God has not given up on unbelieving Israel. The Jewish people are beloved. Based on the covenant and God’s choice.
Once He has unilaterally made a covenant (as He did in His covenant with Abraham, Isaac, Jacob and their descendants), He does not change His mind!
A beautiful example of pure grace! And we see the outworking of this principle in God's dealings with Israel.