Exodus 19:16-20

16 On the morning of the third day, there was thunder and lightning. A thick cloud was there over the mountain. The people heard the noise of a loud trumpet. They were so afraid that their bodies were shaking.

17 Then Moses led the people away from their tents to meet with God. They went and they stood at the edge of the mountain. 18 Smoke covered Mount Sinai because the Lord had come down on the mountain, like a fire. The smoke rose up from the mountain, like smoke from a great fire. The whole mountain shook very much. 19 The noise of the trumpet became louder and louder. Moses spoke to God and God answered him with a loud voice.

20 The Lord came down onto the top of Mount Sinai. Then the Lord told Moses that he must come up to the top of the mountain. So Moses went up the mountain.