Exodus 19:18

14Moses went down from the mountain to the people, and sanctified the people; and they washed their clothes.

15He said to the people, “Be ready by the third day. Don’t have sexual relations with a woman.”

16On 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.

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

18All 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.

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

20The 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.

21The LORD said to Moses, “Go down, warn the people, lest they break through to the LORD to gaze, and many of them perish.

22Let the priests also, who come near to the LORD, sanctify themselves, lest the LORD break out on them.”