John Chrysostom

"And for a great while," it says, "they expected that he would die." But when he shook his hand, and flung off the beast, then they saw and were astonished. And the miracle did not take place suddenly, but the men went by the length of time, "after they had looked a great while," so plainly was there no deceit, no haste here.

Homily on Acts 54 ↗

Theophylact of Ohrid

They thought that Paul's body would be torn apart. "Having waited a long time." The miracle was not revealed suddenly, but the people waited for it for some time. Thus, this occurrence was not a deception or mere trickery. "They said that he was a God." Since they had the custom of calling anyone who did something extraordinary a god, just as the ancients called gods those who, whether by physical strength, like Heracles, performed greater feats than their contemporaries, or drove spectators out of their minds by the art of magic, …

Commentary on Acts ↗

Oecumenius

Therefore when the Barbarians saw this and the certain death escaping them, they thought him to be a god, having the custom, making everything marvelous, to consider as a god; just as they used to call the old gods, either because of some greater strength they exhibited among themselves, as was Heracles; or because by magic they astounded those about them, as was Simon in Samaria. [AMMONIUS]

Commentary on Acts ↗