Deuteronomy 5:23

5:23 Then, when you heard the voice from the midst of the darkness while the mountain was ablaze, all your tribal leaders and elders approached me.

Exodus 19:16-18

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. 19:17 Moses brought the people out of the camp to meet God, and they took their place at the foot of the mountain. 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 20:18-19

20:18 All the people were seeing the thundering and the lightning, and heard the sound of the horn, and saw the mountain smoking – and when the people saw it they trembled with fear and kept their distance. 20:19 They said to Moses, “You speak to us and we will listen, but do not let God speak with us, lest we die.”