Exodus 19:16

19:16 On the third day in the morning there was thunder and lightning and a dense cloud on the mountain, and the sound of a very loud horn; all the people who were in the camp trembled.

Exodus 19:18

19:18 Now Mount Sinai was completely covered with smoke because the Lord had descended on it in fire, and its smoke went up like the smoke of a great furnace, and the whole mountain shook violently.

Exodus 19:20

19:20 The Lord came down on Mount Sinai, on the top of the mountain, and the Lord summoned Moses to the top of the mountain, and Moses went up.