It thundered. The unexpected sound of the voice would confound and amaze them; and though there is no reason to doubt that the words were spoken distinctly (Mt 3:17), yet some of the people, either from amazement or envy, would suppose that this was a mere natural phenomenon.

An angel spake. It was the opinion of many of the Jews that God did not speak to men except by the ministry of angels, Heb 2:2: "The word spoken by angels;" Ga 3:19: "It was ordained by angels in the hand of a mediator."