You see that they are no small gains that we earn from these addresses, and what treasures we should have passed hastily over, unless in this part of the Epistle also we had examined it with accuracy, such, I mean, as was in our power. So if there be found any man of wisdom and spiritual, he will dive even deeper, and find a greater number of pearls. But since some have often made it a question wherefore it was that in this Epistle he addressed so many, which thing he has not done in any other Epistle, we might say that it is owing to his never having seen the Romans yet, that he does this.
And yet one may say, “Well, he had not seen the Colossians either, and yet he did not do anything of the kind.” But these were more honorable than others, and had come there from other cities, as to a safer and more royal city. Since then they were living in a foreign country, and they needed much provision for security, and some of them were of his acquaintance, but some too were there who had rendered him many important services, he with reason commends them by letters; for the glory of Paul was then not little, but so great, that even from his sending them letters, those who had the happiness to have an Epistle to them, gained much protection.
For men not only reverenced him, but were even afraid of him. Had this not been so, he would not have said, who had been “a succorer of many, and of myself also.” And again, “I could wish that myself were accursed.” And to Philemon he wrote and said, “as Paul the aged, and a prisoner of Jesus Christ.” And to the Galatians, “Behold, I Paul say unto you.” And, “You received me even as Jesus Christ.” And writing to the Corinthians he said, “Now some are puffed up, as though I would not come unto you.” And again, “These things I have in a figure transferred to myself and to Apollos, that you might learn in us not to think of men above that which is written.” Now from all these passages it is clear that all had a great opinion of him.
Wishing then that they should feel on easy terms, and be in honor, he addressed each of them, setting forth their praise to the best advantage he might. For one he calls beloved, another kinsman, another both, another fellow-prisoner, another fellow-worker, another approved, another elect. And of the women one he addresses by her title, for he does not call her servant of the Church in an undefined way (because if this were so he would have given Tryphena and Persis this name too), but this one as having the office of deaconess, and another as helper and assistant, another as mother, another from the labors she underwent, and some he addresses from the house they belonged to, some by the name of Brethren, some by the appellation of Saints.
And some he honors by the mere fact of addressing them, and some by addressing them by name, and some by calling them first-fruits, and some by their precedence in time, but more than all, Priscilla and Aquila. (τοὺς περὶ Πρ. κ. ᾿Α.) For even if all were believers, still all were not alike, but were different in their merits. Wherefore to lead them all to greater emulation, he keeps no man's encomiums concealed. For when they who labor more, do not receive the greater reward also, many become more listless.
On this ground even in the kingdom, the honors are not equal, nor among the disciples were all alike, but the three were preëminent above the rest. And among these three again there was a great difference. For this is a very exact method observed by God even to the last. Hence, “one star differs from another star in glory,”, it says. And yet all were Apostles and all are to sit on twelve thrones, and all left their goods, and all companied with Him; still it was the three He took.
And again, to these very three, He said it was possible (ἐ γχωρεῖν) that some might even be superior. “For to sit,” He says, “on My right hand and on My left, is not mine to give, save to those for whom it is prepared.” And He sets Peter before them, when He says, “Lovest thou Me more than these?” And John too was loved even above the rest. For there shall be a strict examination of all, and if you be but little better than your neighbor, if it be even an atom, or anything ever so little, God will not overlook even this. And this even from of old one might see coming out. For even Lot was a righteous man, yet not so, as was Abraham; and Hezekiah again, yet not so as was David: and all the prophets, yet not so as was John.
Source: Homilies on Romans (New Advent)