Romans 11:18-23

But you must not brag about being grafted in to replace the branches that were broken off. You are just a branch, not the root. “Well,” you may say, “those branches were broken off to make room for me.” Yes, but remember—those branches were broken off because they didn’t believe in Christ, and you are there because you do believe. So don’t think highly of yourself, but fear what could happen. For if God did not spare the original branches, he won’t spare you either. 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.