John Chrysostom

Again he uses the phrase of "rising up" to denote their exasperation and wrath. Here we have a great multitude. And observe the difference in the form of accusation: for since Gamaliel had stopped them from finding fault on the former plea, they bring in another charge. The synagogues were diverse: to wit, "Of the Libertines": "of the Cyrenians, i.e. those in the parts beyond Alexandria, of the Alexandrians," etc. …

Homily on Acts 15 ↗

Theophylact of Ohrid

"They entered into a dispute with Stephen." In irritation and anger they argue in order to force him to say something. And he, perhaps, was speaking very openly and was talking about the cessation of the law, or rather, he was not speaking directly but hinting, because if he had spoken clearly, these "certain ones" would have had no need for false witnesses. But notice: he does not take upon himself the right to teach, but is compelled to do so by those who argue with him.

Commentary on Acts ↗

Oecumenius

He says that their frenzy and momentum rose again and that they were not only roused against themselves but also would soon debate and sophisticate with another crowd, perhaps Libertines, and Alexandrians, and Cyrenaicans, and Cilicians, and Asians. And just as the discussion proceeds through another crowd, so likewise the accusation through others, and the plot of tricksters and desperate men. …

Commentary on Acts ↗

Bede

However, there arose some from the synagogue called the Libertines and Cyrenians, etc. And in the Greek text, the name Libertines is written. Now, libertini are called the sons of freedmen, that is, those who, after servitude, were freed and granted liberty. It is therefore evident that those who first rebelled against the faith of Christ were born of a servile stock; who, although they were emancipated from human masters, nonetheless did not cease to be slaves of sin. …

Retractions on Acts ↗