John Chrysostom

"And upon the day of the week, when the disciples came together to break bread, Paul preached unto them, ready to depart on the morrow; and continued his speech until midnight." It was then the season between Easter and Pentecost. See how everything was subordinate to the preaching. It was also, it says, the Lord's day. Not even during night-time was he silent, nay he discoursed the rather then, because of stillness. Mark how he both made a long discourse, and beyond the time of supper itself.

Homily on Acts 43 ↗

Theophylact of Ohrid

Then it was the feast of Pentecost and a Sunday. And even at night Paul did not rest, but conversed then all the more, since it was a time of leisure. See how long he spoke even after supper.

Commentary on Acts ↗

Bede

And he prolonged his speech until midnight. There were many lamps in the upper room. Here we can allegorically say that the upper room signifies the height of spiritual gifts, night the obscurity of the Scriptures, the abundance of lamps the exposition of the hidden sayings, the Lord's Day the remembrance either of the Lord's or our resurrection; and to admonish the spiritual teacher that if at any time, by the sweetness of the resurrection and the joys of eternal life, he will invite his listeners to the heights of virtues, and by …

Commentary on Acts ↗

Cassiodorus

"And on the first day of the week, when they were assembled to break bread." On the day before his departure from Troas, Paul, continuing his speech until midnight, was teaching very earnestly and pleasantly, when it came to pass that one of the young men present, overcome by sleep, fell from the loft and was in danger of death. Paul, embracing him with religious affection, gave him back safe and sound to the people present. …

Complexiones on the Acts of the Apostles ↗