Exodus 19:16
And it came to pass on the third day in the morning, that there were thunders and lightning, and a thick cloud on the mount, and the voice of the trumpet exceeding loud; so that all the people that was in the camp trembled.
Torrey's Topical Textbook—AKJV

Exodus 20:18-20
And all the people saw the thunder, and the lightning, and the noise of the trumpet, and the mountain smoking: and when the people saw it, they removed, and stood afar off.
Torrey's Topical Textbook—AKJV

Deuteronomy 5:5,23-25
(I stood between the LORD and you at that time, to show you the word of the LORD: for you were afraid by reason of the fire, and went not up into the mount;) saying,
Torrey's Topical Textbook—AKJV