Exodus 19:15-17 World English Bible (WEB)
15 He said to the people, “Be ready by the third day. Don’t have sexual relations with a woman.”
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. 17 Moses led the people out of the camp to meet God; and they stood at the lower part of the mountain.