Exodus 19:16 WEB

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

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

¹⁶  It happened on the third day, when it was morning, that 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.

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

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