John Chrysostom

"Salute Andronicus and Junia my kinsmen." This also looks like an encomium. And what follows is much more so. And what sort is this of? "And my fellow-prisoners." For this is the greatest honor, the noble proclamation. And where was Paul a prisoner, that he should call them "my fellow-prisoners?" A prisoner indeed he had not been, but he had suffered things worse than prisoners, in being not an alien only to his country and his family, but in wrestling with famine and continual death, and thousands of other things. …

Homily on Romans 31 ↗

Theophylact of Ohrid

That they are kinsmen of Paul, this does not constitute as great a praise as the fact that they are fellow prisoners with him; for they suffered far more than any prisoner, being dragged from place to place and plundered. It is also significant to be an apostle, especially if one considers that Junia was a woman: all the more significant then to be notable among the apostles. And they were renowned for their deeds. …

Commentary on Romans ↗

Thomas Aquinas

Then he says, greet Andronicus and Junias, whom he describes, first, from their race when he says: my kinsmen. This shows that they were Jews, about whom he said above: who are my kinsmen according to the flesh (Rom 9:3). Second, from the suffering they endured for Christ, saying and fellow prisoners. For they had been in prison once with the Apostle: with far more imprisonments (2 Cor 11:23). …

Commentary on Romans ↗