Jeremiah 32:37 Behold, I will gather them out of all countries, whither I have driven them in mine anger, and in my fury, and in great wrath; and I will bring them again unto this place, and I will cause them to dwell safely: 38 And they shall be my people, and I will be their God: 39 And I will give them one heart, and one way, that they may fear me for ever, for the good of them, and of their children after them: 40 And I will make an everlasting covenant with them, that I will not turn away from them, to do them good; but I will put my fear in their hearts, that they shall not depart from me.
God has been dealing with the nation of Israel all through the Old Testament. There comes a point where He places them to one side. The church and its ministry is put in place. Right now we are in sort of a parenthesis in history. We are the wild branch, the church, that has been grafted in. Israel is coming back. God will use them again. He has not abandoned them.
He will one day gather them back to the land He promised them. He will then change their hearts and build in them what should have always been there. God is at work and will do great things.
If God will not keep His promises to Israel then we would have no hope that He would literally keep His promises to us!