Romans 11:18

"But if the firstfruits are holy, so is the lump; and if the root is holy, so are the branches. But if some of the branches were broken off, and you, though you were a wild olive, were grafted in among them and became a sharer in the root and the fatness of the olive tree, do not boast against the branches. But if you do boast, it is not you who bear the root, but the root you. You say then: The branches were broken off so that I might be grafted in. Well: they were broken off because of unbelief. But you stand by faith: do not be proud in your thinking, but fear. For if God did not spare the natural branches, neither will he spare you. Behold, then, the goodness and the severity of God: toward those indeed who fell, severity; but toward you, goodness, if you continue in goodness. Otherwise you too will be cut off, and they, if they do not continue in unbelief, will be grafted in. For God is able to graft them in again. For if you were cut out of the olive tree which is wild by nature, and contrary to nature were grafted into the good olive tree, how much more shall these, who are according to nature, be grafted into their own olive tree?" I do not know how those who come from the school of Valentinus and Basilides, failing to hear these things thus spoken by Paul, suppose that there is a nature of souls which is always saved and never perishes, and another which always perishes and is never saved: when Paul plainly says that the branches of the good olive tree were broken off because of their own unbelief, and stood in need of the vengeance of divine severity; and again that the branches of the wild olive — which among them is set down as a nature that is lost — were grafted into the root and fatness of the olive tree. But to those people, indeed, an easy answer may be given by these words. […]

"Boast not against the branches." He seems indeed to be comforting the Jew, but points out his vileness and extreme dishonor. And this is why he says not, "boast not," but, "boast not against" do not boast against them so as to sunder them. For it is into their place that ye have been set, and their goods that ye enjoy. Do you observe how he seems to be rebuking the one, while he is sharp upon the other? "But if thou boast," he says, "thou bearest not the root, but the root thee." Now what is this to the branches that are cut off? Nothing. For, as I said before, while seeming to devise a sort of weak shadow of consolation, and in the very midst of his aiming at the Gentile, he gives them a mortal blow; for by saying, "boast not against them," and, "if thou boast, thou bearest not the root," he has shown the Jew that the things done deserved boasting of, even if it was not right to boast, thus at once rousing him and provoking him to faith, and smiting at him, in the attitude of an advocate, and pointing out to him the punishment he was undergoing, and that other men had possession of what were their goods.

It displeases God if someone rejoices at the misfortune of others, as Solomon says. In any case, the Jews were not rejected for the sake of the Gentiles. Rather, it was because they were rejected that they gave an opportunity for the gospel to be …

Then when he says, but if you boast, he gives the reason for his admonition, saying: but if in spite of this admonition you boast by insulting the Jews, who stand upright or have been cut off, you should consider as a check to your …

Therefore, do not be arrogant and do not boast against the branches. What good is this to the branches that were broken off? For it is the root that supports. Do you see how he only praises the Jews in appearance, seeking merely to console …