Exodus 19:14-16

Amplified Bible

¹⁴ So Moses went down from the mountain to the people and sanctified them [for God’s sacred purpose], and they washed their clothes. ¹⁵ He said to the people, “Be prepared for the third day; do not ^[a]be intimate with a woman.”

¹⁶ So it happened on the third day, when it was morning, that there were thunder and flashes of lightning, and a thick cloud was on the mountain, and a very loud blast was sounded on a ram’s horn, so that all the people who were in the camp trembled.