John Chrysostom

"And when the congregation was broken up, many of the Jews and worshipping proselytes followed Paul and Barnabas" - after this point he puts Paul first - "who, speaking unto them, persuaded them to continue in the grace of God." Do you observe the eagerness, how great it is? They "followed" them, it says. Why did they not baptize them immediately? It was not the proper time: there was need to persuade them in order to their steadfast abiding therein.

Homily on Acts 30 ↗

Oecumenius

Respecting here and going forward those who are fervent and passionate in the worship surrounding it, he calls them rather zealots than the others. For such persons accepted the faith in Christ sooner than others, being able to perceive its superiority and greatness, and not from human passion, but from a regard for truth and a love of devotion and the reverence they previously held, becoming zealots for that. …

Commentary on Acts ↗

Bede

They were speaking, urging them to remain in the grace of God. Hence in the Greek follows a verse, which our Codices do not have: But the word was spread throughout the whole city, and then what we have is added: On the next Sabbath, almost the whole city gathered to hear the word of God.

Retractions on Acts ↗