John Chrysostom

"For if the casting away of them be the reconciling of the world, what shall the receiving of them be but life from the dead?" Yet this again condemns them, since, while others gained by their sins, they did not profit by other men's well doings. But if he asserts that to be their doing which necessarily happened, be not surprised: since (as I have said several times) it is to humble these, and to exhort the other, that he throws his address into this form. …

Homily on Romans 19 ↗

Theophylact of Ohrid

If, he says, having been angered at them, He granted so much to others and made enemies into friends, what will He not grant when He receives them? Then there will be "life from the dead," that is, unending blessings; for He indicates these by the word "life." At the same time, he also hints at something more exalted, namely that just as the resurrection from the dead will not depend on the acceptance of the Jews, so too the salvation of others will not depend on them either, if they do not have faith. …

Commentary on Romans ↗

Thomas Aquinas

Then when he says, for if, he assigns the reason for his interest, namely, that the conversion of the Jews would contribute to the salvation of the gentiles. Hence he says, for if the loss of them, i.e., their unbelief and disobedience, as a slave is said to be lost when he flees from the care and obedience of his master: my people have been a lost flock (Jer 50:6). …

Commentary on Romans ↗