And the LORD said to Moses, “Behold, I am coming to you in a thick cloud, that the people may hear when I speak with you, and may also believe you forever.”

When Moses told the words of the people to the LORD, the LORD said to Moses, “Go to the people and consecrate them today and tomorrow, and let them wash their garments and be ready for the third day. For on the third day the LORD will come down on Mount Sinai in the sight of all the people. And you shall set limits for the people all around, saying, ‘Take care not to go up into the mountain or touch the edge of it. Whoever touches the mountain shall be put to death. No hand shall touch him, but he shall be stoned or shot; whether beast or man, he shall not live.’ When the trumpet sounds a long blast, they shall come up to the mountain.” So Moses went down from the mountain to the people and consecrated the people; and they washed their garments. And he said to the people, “Be ready for the third day; do not go near a woman.”

(ESV)