Romans 11:22-25

Notice how God is both kind and severe. He is severe toward those who disobeyed, but kind to you if you continue to trust in his kindness. But if you stop trusting, you also will be cut off. And if the people of Israel turn from their unbelief, they will be grafted in again, for God has the power to graft them back into the tree. You, by nature, were a branch cut from a wild olive tree. So if God was willing to do something contrary to nature by grafting you into his cultivated tree, he will be far more eager to graft the original branches back into the tree where they belong. I want you to understand this mystery, dear brothers and sisters, so that you will not feel proud about yourselves. Some of the people of Israel have hard hearts, but this will last only until the full number of Gentiles comes to Christ.