John Chrysostom, on Rom 1:13

Here is a compliance great as that of slaves, and a plain exhibition of his excellent temper! For, that he was let, he says, but why, he does not go on to say. For he does not pry into the command of his Master, but only obeys. And yet one might expect a person to start questions, as to why God hindered a city so conspicuous and great, and towards which the whole world was looking, from enjoying such a teacher, and that for so long a time. For he that had overcome the governing city, could easily go on to the subjects of it. But he that let alone the more royal one, and lay in wait about the dependents, had the main point left neglected. But none of these things does he busy himself with, but yields to the incomprehensibleness of Providence, thereby both showing the right tone of his soul, and instructing us all never to call God to account for what happens, even though what is done seem to trouble the minds of many. For the Master's part it is alone to enjoin, the servants' to obey. And this is why he says, that he was let, but not for what cause; for he means, even I do not know; ask not then of me the counsel or mind of God. For why, tell me, do you even seek to learn it? do you not know that all things are under His care, that He is wise, that He doeth nothing at a mere hazard, that He loveth thee more than they who begat thee, and goes exceeding far beyond a father's yearnings of affection to thee, and a mother's anxiousness. Seek then no more, and go not a step further; for this is sufficient consolation for thee: since even then it was well ordered for the Romans. And if thou knowest not the manner, take it not to heart: for this is a main feature of faith, even when in ignorance of the manner of the dispensation, to receive what is told us of His Providence.

Paul then having succeeded in what he was earnest about (and what was this? to show that it was not as slighting them that he did not come to them, but because, though greatly desiring it, he was hindered), and having divested himself of the accusation of remissness, and having persuaded them that he was not less desirous to see them than themselves, further shows his love to them by other things. For even when I was hindered he means, I did not stand aloof from the attempt, but I kept attempting always yet was always hindered, yet never did I stand aloof thus, without falling out with the will of God, still keeping my love. For by his purposing it to himself and not standing aloof from it, he showed his affection; but through his being hindered and yet not struggling against it, all his love to God. "That I might have some fruit among you also." Yet he had told them the cause of his longing before, and shown that it was becoming him; but still here also, he states it, clearing away all their suspicion. For since the city was conspicuous, and in the whole extent of sea and land had no equal to many even the mere desire of becoming acquainted with it became a reason for a journey to it; that they might not think anything of the sort about Paul, or suspect that, merely with a view to glory in claiming them to himself he desired to be present there, he repeatedly lays down the ground of his desire, and before he says, it was that "I may impart to you some spiritual gift," that I desired to see you; but here more clearly, "that I might have some fruit among you also even as among other Gentiles." The rulers he puts with the subjects, and after the countless triumphs and victories and the glory of the consuls, he puts them with the barbarians, and with good reason too. For where the nobility of faith is, there is none barbarian, none Grecian, none stranger, none citizen, but all mount up to one height of dignity.