Romans 11:21

for if God spared not the natural branches, neither will he spare thee. [Faith justified no boast, yet faith constituted the only divinely recognized distinction in the Gentiles' favor, in estimating between the Gentile Christian and the cast-off Jew. All the past history of the Jew stood in his favor; therefore the Gentile has vastly more reason to fear than had the Jew; for if natural branches fell through false pride which induced unbelief, how much more likely the adopted branches were to be cut off. Again, he had more reason for fear than for pride; for being on trial as the Jews had been, he was succumbing to the same sin of self-righteous pride, and more liable to suffer the same rejection. Paul now presents the even-balanced equality of Jew and Gentile if weighed in the scales of merit instead of the new scales of grace-toward-faith.]