Paul had to deal with the same question and he answered it in Romans 11...the whole chapter is instructive in that he compares Jews to natural branches of a tree and gentiles as grafted in branches on that same tree.
Rom 11:25 For I do not desire, brethren, that you should be ignorant of this mystery, lest you should be wise in your own opinion, that blindness in part has happened to Israel until the fullness of the Gentiles has come in.
Rom 11:26 And so all Israel will be saved, as it is written: "THE DELIVERER WILL COME OUT OF ZION, AND HE WILL TURN AWAY UNGODLINESS FROM JACOB;
Rom 11:27 FOR THIS IS MY COVENANT WITH THEM, WHEN I TAKE AWAY THEIR SINS."
Rom 11:28 Concerning the gospel they are enemies for your sake, but concerning the election they are beloved for the sake of the fathers.
Everything promised to Israel will happen. The promises of God are irrevocable. Rom 11:29 For the gifts and the calling of God are irrevocable.
You admit that there is a nation of Israel which will come to faith in Jesus Christ, the true Israel with whom God made the New Covenant and you admit that it is that Israel, the physical descendants of Isaac, whom God calls the "children of promise" who will be reconciled to the Father through Jesus Christ and which be the nation that fulfills the New Covenant, not the Church. You admit that this nation, according to the very words of God, will have their sins taken away and be saved and redeemed.
Finally. Thank you.