Job 37:2 - Matthew Poole's English Annotations on the Holy Bible

It seems not improbable, that whilst Elihu was speaking it thundered greatly, and that tempest was begun wherewith God ushered in his speech, as it here follows, Job 38:1, and that this occasioned his return to that subject of which he had discoursed before, and his exhortation to them to mind it with deeper attention. The noise of his voice; or, his voice (to wit, the thunder, which is called a voice, Exodus 20:18, and God's voice, Psalms 29:4) with trembling; because the thunder is an effect or evidence of God's mighty power, and ofttimes of his anger also. The sound that goeth out of his mouth; as the voice (and thunder is God's voice) goeth out of man's mouth. Or, that is produced by God's word or command, which is oft signified by his mouth.