Adam Clarke on Acts 16:29

He called for a light - That he might see how things stood, and whether the words of Paul were true; for on this his personal safety depended.

Came trembling - Terrified by the earthquake, and feeling the danger to which his own life was exposed.

Fell down before Paul and Silas - The persons whom a few hours before he, according to his office, treated with so much asperity, if not cruelty, as some have supposed; though, by the way, it does not appear that he exceeded his orders in his treatment of the apostles.