John Chrysostom

"Salute Asyncritus, Phlegon, Hermas, Patrobas, Hermes, and the brethren which are with them." Here do not be looking to how he starts them without any encomium, but how he did not reckon them, though far inferior, as it seems, to all, unworthy of being addressed by him. Or rather even this is no slight praise that he even calls them brethren, as also those that are after them he calls saints. ...

Homily on Romans 31 ↗

Theophylact of Ohrid

Here do not look at the fact that he enumerates them without ascribing any praise to them, but at the fact that although they were far below everyone else, they nevertheless were deemed worthy of a greeting from the apostle. Or rather, he did ascribe praise to them as well, when he called them brethren.

Commentary on Romans ↗

Jerome

Hermas whom the apostle Paul mentions in writing to the Romans "Salute Phlegon, Hermes, Patrobas, Hermas and the brethren that are with them" is reputed to be the author of the book which is called Pastor and which is also read publicly in some churches of Greece. It is in fact a useful book and many of the ancient writers quote from it as authority, but among the Latins it is almost unknown.

De Viris Illustribus (On Illustrious Men), Section 10 ↗

Thomas Aquinas

Then he says, greet Asyncritus, Phlegon, Hermes, Patrobas, Hermas, and the brethren who are with them. He greets them together, because they lived together in harmony: God gives the lonely a home to live in (Ps 68:6).

Commentary on Romans ↗