John Chrysostom

"Thou wilt say then," he goes on, "The branches were broken off that I might be grafted in." Again he establishes, by way of objection, the opposite to the former position, to show that what he said before, he had not said as directly belonging to the subject, but to draw them to him. For it was no longer by their fall that salvation came to the Gentiles, nor was it their fall that was the riches of the world. Nor was it by this that we were saved, because they had fallen, but the reverse. …

Homily on Romans 19 ↗

Theophylact of Ohrid

Here he proves that the Gentiles were not chosen in place of the Jews because the Jews sinned, but for the faith which the Gentiles displayed. So where he seems to cast down the Gentile, there he shows that the fall of the Jews was inexcusable. But he corrects both groups. You, Gentile, will say that the branches were broken off so that you might be grafted in? Yes, they were broken off, but by their own unbelief, and not because God owed you that honor: for "you stand by faith," having been grafted into the root. …

Commentary on Romans ↗

Thomas Aquinas

Then when he says, you will say then, he excludes an objection from the gentiles: first, he presents the objection; second, he excludes it from a consideration of divine justice, at well; third, he urges them to diligently consider God's judgments, at see then the goodness. First, therefore, he says: therefore, O gentile, who boasts against the Jews, you might say: the branches were broken off that I might be grafted in, i.e., God permitted the Jews to fall from faith, so that I might enter into faith. …

Commentary on Romans ↗