Three times in Romans 11, the apostle Paul warns the Gentile Christians of Rome against arrogance (vv. 18, 20, 25).
The apostle tells them, "if some of the branches were broken off [from the cultivated olive tree] and you, a wild olive shoot, were grafted in their place to share the richness of the olive tree" (Rom. 11:17).
They are told: "do not boast over the branches" (Rom. 11:18), that is over the Jews who did not believe in Jesus.