John Chrysostom

"Nevertheless, I have written the more boldly unto you in some sort." Observe the lowly-mindedness of Paul, observe his wisdom, how he gave a deep cut in the former part, and then when he had succeeded in what he wished, how he uses much kindliness next. For even without what he has said, this very confession of his having been bold were enough to unstring their vehemency. …

Homily on Romans 29 ↗

Theophylact of Ohrid

The Romans enjoyed respect and were quite arrogant. Therefore he heals them when he says, "I have written to you with some boldness"; for by this word he greatly humbles them. But he was not satisfied even with this, and added: "in part," that is, somewhat and briefly, and moreover not as one instructing, but "as if by way of reminder," that is, gently reminding.

Commentary on Romans ↗

Clement of Rome

These things therefore being manifest to us, and since we look into the depths of the divine knowledge, it behooves us to do all things in [their proper] order, which the Lord has commanded us to perform at stated times. He has enjoined offerings [to be presented] and service to be performed [to Him], and that not thoughtlessly or irregularly, but at the appointed times and hours. …

Letter to the Corinthians (Clement) ↗

Thomas Aquinas

Then when he says, but I have written to you, he gives the true cause why he had admonished and corrected them. In regard to this he does two things: first, he shows that this belongs to the authority committed to him by his apostolate; second, he shows how he used this power, at I have, therefore, glory. …

Commentary on Romans ↗