So Moses went down from the mountain to the people and sanctified the people, and they washed their clothes.
Exodus 19:14
Surrounding context
19:13 Not a hand shall touch him, but he shall surely be stoned or shot with an arrow; whether man or beast, he shall not live.' When the trumpet sounds long, they shall come near the mountain."
19:14 So Moses went down from the mountain to the people and sanctified the people, and they washed their clothes.
19:15 And he said to the people, "Be ready for the third day; do not come near your wives."