And none, he means, can say that my words are a mere boast. For of this priestly ministry of mine, the signs that I have, and the proofs of the appointment too, are many. Not the long garment (ποδήρης) and the bells as they of old, nor the mitre and the turban (κίδαρις), but signs and wonders, far more awful than these. Nor can it be said that I have been entrusted indeed with the charge, but yet have not executed it. Or rather, it is not I that have executed, but Christ. Wherefore also it is in Him that I boast, not about common things, but about spiritual. And this is the force of, “in things which pertain to God.” For that I have accomplished the purpose for which I was sent, and that my words are not mere boast, the miracles, and the obedience of the Gentiles show. “For I will not dare to speak of any of those things which Christ has not wrought by me, to make the Gentiles obedient by word and deed, through signs and wonders, by the power of the Spirit of God.” See how violently he tries to show that the whole is God's doing, and nothing his own. For whether I speak anything, or do anything, or work miracles, He does all of them, the Holy Spirit all. And this he says to show the dignity of the Holy Spirit also. See how these things are more wondrous and more awful than those of old, the sacrifice, the offering, the symbols. For when he says, “in word and deed, through mighty signs and wonders,” he means this, the doctrine, the system (φιλοσοφίαν) relating to the Kingdom, the exhibition of actions and conversation, the dead that were raised, the devils that were cast out, and the blind that were healed, and the lame that leaped, and the other marvellous acts, all whereof the Holy Spirit wrought in us. Then the proof of these things (since all this is yet but an assertion) is the multitude of the disciples. Wherefore he adds, “So that from Jerusalem, and round about unto Illyricum, I have fully preached the Gospel of Christ.” Count up then cities, and places, and nations, and peoples, not those under the Romans only, but those also under barbarians. For I would not have you go the whole way through Phœnicia, and Syria, and the Cilicians, and Cappadocians, but reckon up also the parts behind, the country of the Saracens, and Persians, and Armenians, and that of the other savage nations. For this is why he said, “round about,” that you might not only go through the direct high road, but that you should run over the whole, even the southern part of Asia in your mind. And as he ran over miracles thick as snow, in a single word, by saying, “through mighty signs and wonders,” so he has comprehended again endless cities, and nations, and peoples, and places, in this one word “round about.” For he was far removed from all boasting. And this, he said on their account, so that they should not be conceited about themselves. And at the beginning he said, that “I might have some fruit among you also, even as among other Gentiles.” But here he states the compulsion of his priesthood. For as he had spoken in a sharper tone, he shows also by it his power more clearly. This is why he there only says, “even as among other Gentiles.” But here he insists on the topic fully, so that the conceit may be pruned away on all grounds. And he does not merely say, preached the Gospel, but “have fully preached the Gospel of Christ.”
Ver. 20. “Yea, so have I strived to preach the Gospel, not where Christ was named.”
See here another preeminence; that he had not only preached the Gospel to so many, and persuaded them, but he did not even go to those who had become disciples. So far was he from thrusting himself upon other men's disciples, and from doing this for glory's sake, that he even made it a point to teach those who had not heard. For neither does he say where they were not persuaded, but “where Christ was not even named,” which is more. And what was the reason why he had this ambition? “Lest I should build,” he says, “upon another man's foundation.”
This he says to show himself a stranger to vanity, and to instruct them that it was not from any love of glory, or of honor from them, that he came to write, but as fulfilling his ministry, as perfecting his priestly duty, as loving their salvation. But he calls the foundation of the Apostles “another man's,” not in regard to the quality of the person, or the nature of preaching, but in regard to the question of reward. For it was not that the preaching was that of another man, but so far as it went to another man's reward. For the reward of the labors of others was, to this man, another man's. Then he shows that a prophecy was fulfilled also saying,
Ver. 21. “As it is written, To whom He was not spoken of, they shall see, and they that have not heard shall understand.”
You see he runs to where the labor is more, the toil greater.
Ver. 22. “For which cause also I have been much hindered from coming to you.”
Observe again, how he makes the end of the like texture with the introduction. For while he was quite at the beginning of the Epistle, he said, “Oftentimes I purpose to come unto you, but was let hitherto.” But here he gives the cause also by which he was let, and that not once, but twice even, aye, and many times. For as he says there, “oftentimes I purposed to come to you,” so here too, “I have been much (or often, τὰ πολλὰ) hindered from coming to you.” Now it is a thing which proves a very strong desire, that he attempted it so often.
Ver. 23. “But now having no more place in these parts.”
See how he shows that it was not from any coveting of glory from them, that he both wrote and was also coming. “And having a great desire to come to you these many years,”
Ver. 24. “Whenever I take my journey into Spain, I trust to see you in my journey; and to be brought on my way thitherward by you, if first I be somewhat filled with your company,”
Source: Homilies on Romans (New Advent)