Thomas Aquinas — on Rom 11:13 (Commentary on Romans)

“Then when he says, for I say to you, gentiles, he shows the same things by revealing the purpose of his ministry, which he first states; second, he assigns the reason, at for if the loss. In regard to the first it should be noted that whereas the previous parts of the epistle were directed to all the believers in Rome, whether from the Jews or from the gentiles, he is now directing his words to the converted gentiles. He says, therefore: I have stated that their fullness will mean riches for the world. As testimony to this I say to you, gentiles, i.e., gentiles converted to the faith: I said, 'behold me' to a nation that did not call upon my name (Isa 65:1). This, I repeat, I say to you: as long indeed as I am the apostle of the gentiles, the special care of whom has fallen to me on account of the office entrusted to me: they gave to me and to Barnabas the right hands of fellowship: that we should go unto the gentiles, and they unto the circumcision (Gal 2:9); for this was I appointed a preacher and apostle, a teacher of the gentiles in faith and truth (1 Tim 2:7); I will honor my ministry, not with things that pertain to worldly honor: but first by adorning it with good morals: as servants of God we commend ourselves in every way in much patience. (2 Cor 6:4). Second, by performing extra works to which he was not bound: what is my reward then? That preaching the Gospel, I may deliver the Gospel without charge, that I abuse not my power in the Gospel (1 Cor 9:18). Third, by increasing his solicitude for the salvation of all: besides those things which are without: my daily instance, the solicitude for all the churches (2 Cor 11:28).”