9 The Lord said to Moses, “Behold, I will come to you in a thick cloud, so that the people may hear when I speak with you and may also believe in you forever.” Then Moses told the words of the people to the Lord.
10 The Lord also said to Moses, “Go to the people and consecrate them today and tomorrow, and let them wash their garments; 11 and let them 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. 12 You shall set bounds for the people all around, saying, ‘[a]Beware that you do not go up on the mountain or touch the border of it; whoever touches the mountain shall surely be put to death. 13 No hand shall touch him, but he shall surely be stoned or [b]shot through; whether beast or man, he shall not live.’ When the ram’s horn sounds a long blast, they shall come up to the mountain.” 14 So Moses went down from the mountain to the people and consecrated the people, and they washed their garments. 15 He said to the people, “Be ready for the third day; do not go near a woman.”
16 So it came about on the third day, when it was morning, that there were [c]thunder and lightning flashes and a thick cloud upon the mountain and a very loud trumpet sound, so that all the people who were in the camp trembled. 17 And Moses brought the people out of the camp to meet God, and they stood at the [d]foot of the mountain.
18 Now Mount Sinai was all in smoke because the Lord descended upon it in fire; and its smoke ascended like the smoke of a furnace, and the whole mountain [e]quaked violently. 19 When the sound of the trumpet grew louder and louder, Moses spoke and God answered him with [f]thunder. 20 The Lord came down on Mount Sinai, to the top of the mountain; and the Lord called Moses to the top of the mountain, and Moses went up. 21 Then the Lord spoke to Moses, “Go down, [g]warn the people, so that they do not break through to the Lord to gaze, and many of them [h]perish. 22 Also let the priests who come near to the Lord consecrate themselves, or else the Lord will break out against them.” 23 Moses said to the Lord, “The people cannot come up to Mount Sinai, for You [i]warned us, saying, ‘Set bounds about the mountain and consecrate it.’” 24 Then the Lord said to him, “[j]Go down and come up again, you and Aaron with you; but do not let the priests and the people break through to come up to the Lord, or He will break forth upon them.” 25 So Moses went down to the people and told them. – Exodus 19:9-25