Exodus 19:1-12 ESV
On the third new moon after the people of Israel had gone out of the land of Egypt, on that day they came into the wilderness of Sinai. They set out from Rephidim and came into the wilderness of Sinai, and they encamped in the wilderness. There Israel encamped before the mountain, while Moses went up to God. The LORD called to him out of the mountain, saying, “Thus you shall say to the house of Jacob, and tell the people of Israel: ‘You yourselves have seen what I did to the Egyptians, and how I bore you on eagles’ wings and brought you to myself. Now therefore, if you will indeed obey my voice and keep my covenant, you shall be my treasured possession among all peoples, for all the earth is mine; and you shall be to me a kingdom of priests and a holy nation.’ These are the words that you shall speak to the people of Israel.”
So Moses came and called the elders of the people and set before them all these words that the LORD had commanded him. All the people answered together and said, “All that the LORD has spoken we will do.” And Moses reported the words of the people to the LORD. 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.
ESV: English Standard Version 2016