What does Romans 11:22 mean?
In the previous verse, Paul warned the Gentile Christians that the only reason they had a place in the family of God was because of their faith in Christ. Without that faith, God was just as likely to "prune" them from His tree as He did to the Jewish people who refused to believe in Jesus. Their status was absolutely not on the basis of their own good works (Romans 3:10, 20) or anything other than the grace of God (Romans 11:6).Paul now wants to make sure his readers don't miss these two pillars of God's nature. He is simultaneously kind and uncompromising, based only on a person's faith in Christ. God is holy, so He must be firm toward those who have fallen by their lack of faith in Christ. God is kind to the Gentile Christians because of their faith in Christ. They must continue in God's kindness by continuing to trust in Christ. Without faith in Christ, God will cut them off, as well.
Context is crucial in any passage, but this verse is particularly easy to misunderstand when read by itself. The issue at hand is not being "cut off" from eternal salvation, as the following verses will show. God had "cut off" some of Israel for their rejection of Him, and "grafting in" Gentiles. Paul is still referring to "the Gentiles" as a group, as much as to Israel as a nation. If "the Gentiles" act as coldly and stubbornly towards God as Israel had, God is more than willing and able to deem them "cut off" and suffer as a result. The context here is not about eternity, but the relationship and communion with God. Similar themes are explored in passages such as Hebrews chapters 3 and 4.