John 12:29 - Matthew Poole's English Annotations on the Holy Bible

The people said that it thundered; nor, it may be, were they mistaken, saving only in this, that they thought it was nothing else but thunder (being possibly at such a distance, as they could not distinctly hear the voice); for it was God's way, when he spake unto his people by a voice, to have that voice, for the greater declaration of the Divine majesty, attended with thunderings and lightnings: thus it was at the giving of the law upon Mount Sinai; thus we read in John's visions, Revelation 4:5, Revelation 8:5, of lightnings, and thunderings, and voices, which proceeded from God's throne. Others said, An angel spake to him: it was the general opinion of the Jews, that God always, when by voice he revealed his mind to his people, made use of an angel to do it by; hence, probably, as those who were at such a distance that they heard no voice, thought it was nothing but thunder; so those who are so nigh as, besides the thunder, to hear a voice, said, It was an angel that spake with him.