On the third new moon after the Israelites had gone out of the land of Egypt, on that very day, they came into the wilderness of Sinai.
They had journeyed from Rephidim, entered the wilderness of Sinai, and camped in the wilderness; Israel camped there in front of the mountain.
Then Moses went up to God; the Lord called to him from the mountain, saying, "Thus you shall say to the house of Jacob, and tell the Israelites:
You 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 obey my voice and keep my covenant, you shall be my treasured possession out of all the peoples. Indeed, the whole earth is mine,
but you shall be for me a priestly kingdom and a holy nation. These are the words that you shall speak to the Israelites."
So Moses came, summoned the elders of the people, and set before them all these words that the Lord had commanded him.
The people all answered as one: "Everything that the Lord has spoken we will do." Moses reported the words of the people to the Lord.
Then the Lord said to Moses, "I am going to come to you in a dense cloud, in order that the people may hear when I speak with you and so trust you ever after." When Moses had told the words of the people to the Lord,
the Lord said to Moses: "Go to the people and consecrate them today and tomorrow. Have them wash their clothes
and prepare for the third day, because on the third day the Lord will come down upon Mount Sinai in the sight of all the people.
You shall set limits for the people all around, saying, "Be careful not to go up the mountain or to touch the edge of it. Any who touch the mountain shall be put to death.
No hand shall touch them, but they shall be stoned or shot with arrows; whether animal or human being, they shall not live.' When the trumpet sounds a long blast, they may go up on the mountain."
References for Exodus 19:13
So Moses went down from the mountain to the people. He consecrated the people, and they washed their clothes.
And he said to the people, "Prepare for the third day; do not go near a woman."
On the morning of the third day there was thunder and lightning, as well as a thick cloud on the mountain, and a blast of a trumpet so loud that all the people who were in the camp trembled.
Moses brought the people out of the camp to meet God. They took their stand at the foot of the mountain.
Now Mount Sinai was wrapped in smoke, because the Lord had descended upon it in fire; the smoke went up like the smoke of a kiln, while the whole mountain shook violently.
As the blast of the trumpet grew louder and louder, Moses would speak and God would answer him in thunder.
When the Lord descended upon Mount Sinai, to the top of the mountain, the Lord summoned Moses to the top of the mountain, and Moses went up.
Then the Lord said to Moses, "Go down and warn the people not to break through to the Lord to look; otherwise many of them will perish.
Even the priests who approach the Lord must consecrate themselves or the Lord will break out against them."
Moses said to the Lord, "The people are not permitted to come up to Mount Sinai; for you yourself warned us, saying, "Set limits around the mountain and keep it holy.' "
The Lord said to him, "Go down, and come up bringing Aaron with you; but do not let either the priests or the people break through to come up to the Lord; otherwise he will break out against them."
So Moses went down to the people and told them.