See then the goodness and severity of God. Toward those who fell, severity; but toward you, goodness, if you continue in his goodness; otherwise you also will be cut off. They also, if they don’t continue in their unbelief, will be grafted in, for God is able to graft them in again. For if you were cut out of that which is by nature a wild olive tree, and were grafted contrary to nature into a good olive tree, how much more will these, which are the natural branches, be grafted into their own olive tree? For I don’t desire you to be ignorant, brothers, of this mystery, so that you won’t be wise in your own conceits, that a partial hardening has happened to Israel, until the fullness of the Gentiles has come in,
Paul continues on with the illustration about Jews and Gentiles and God’s good tree but this time he says clearly that God does have a future for Israel. He calls it a mystery. Paul records in the Bible that the Jews are experiencing a temporary and partial “hardening.” Paul exposes this mystery specifically so that we “won’t be wise” in our “own conceits.”
The simple fact is that God is able to remove and add any branches He wants.
The important thing for all of us to remember is that we should “continue in his goodness.” Isn’t it interesting that it didn’t say to “continue in goodness?” The word “his” is extremely important. It is the difference between heaven and hell. If we continue in the pride of our own goodness, we will be cut off from God’s tree because we never really allowed God’s life to flow into us. If we allow His life to flow into us, then we will live and grow as a part of God’s tree. We must remain in His goodness and realize that we actually don’t have any goodness of ourselves. When Jesus was speaking to His disciples, He mentioned this.
Remain in me, and I in you. As the branch can’t bear fruit by itself, unless it remains in the vine, so neither can you,
unless you remain in me. I am the vine. You are the branches. He who remains in me, and I in him, the same bears much fruit, for apart from me you can do nothing.