Exodus 19:16-20

19:16 On the third day, when it was morning, there were thunders and lightnings, and a thick cloud on the mountain, and the sound of an exceedingly loud trumpet; and all the people who were in the camp trembled.

19:17 Moses led the people out of the camp to meet God; and they stood at the lower part of the mountain.

19:18 All of Mount Sinai smoked, because the LORD descended on it in fire; and its smoke ascended like the smoke of a furnace, and the whole mountain quaked greatly.

19:19 When the sound of the trumpet grew louder and louder, Moses spoke, and God answered him by a voice.

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