Exodus 19:10-17

10The Lord also said to Moses, “Go to the people and consecrate them today and tomorrow [that is, prepare them for My sacred purpose], and have them wash their clothes

11and be ready by the third day, because on the third day the Lord will come down on Mount Sinai [in the cloud] in the sight of all the people.

12You shall set barriers for the people all around [the mountain], saying, ‘Beware that you do not go up on the mountain or touch its border; whoever touches the mountain must be put to death.

13No hand shall touch him [that is, no one shall try to save the guilty party], but the offender must be stoned or shot through [with arrows]; whether man or animal [that touches the mountain], he shall not live.’ When the ram’s horn sounds a long blast, they shall come up to the mountain.”

14So Moses went down from the mountain to the people and sanctified them [for God’s sacred purpose], and they washed their clothes.

15He said to the people, “Be prepared for the third day; do not be intimate with a woman.”

16So 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.

17Then Moses brought the people out of the camp to meet God, and they stood and presented themselves at the foot of the mountain.