Exodus 19:9-17

Then the LORD said to Moses, “I will come to you in a thick cloud, Moses, so the people themselves can hear me when I speak with you. Then they will always trust you.” Moses told the LORD what the people had said. Then the LORD told Moses, “Go down and prepare the people for my arrival. Consecrate them today and tomorrow, and have them wash their clothing. Be sure they are ready on the third day, for on that day the LORD will come down on Mount Sinai as all the people watch. Mark off a boundary all around the mountain. Warn the people, ‘Be careful! Do not go up on the mountain or even touch its boundaries. Anyone who touches the mountain will certainly be put to death. No hand may touch the person or animal that crosses the boundary; instead, stone them or shoot them with arrows. They must be put to death.’ However, when the ram’s horn sounds a long blast, then the people may go up on the mountain.” So Moses went down to the people. He consecrated them for worship, and they washed their clothes. He told them, “Get ready for the third day, and until then abstain from having sexual intercourse.” On the morning of the third day, thunder roared and lightning flashed, and a dense cloud came down on the mountain. There was a long, loud blast from a ram’s horn, and all the people trembled. Moses led them out from the camp to meet with God, and they stood at the foot of the mountain.