Exactly three months after the people of Israel left Egypt, they came to the Desert of Sinai.
References for Exodus 19:1
After they started out from Rephidim, they entered the Desert of Sinai. They camped there in the desert in front of the mountain.
Then Moses went up to God. The LORD called out to him from the mountain. He said, "Here is what I want you to say to my people, who came from Jacob's family. Tell the Israelites,
'You have seen for yourselves what I did to Egypt. You saw how I carried you on the wings of eagles and brought you to myself.
" 'Now obey me completely. Keep my covenant. If you do, then out of all of the nations you will be my special treasure. The whole earth is mine.
But you will be a kingdom of priests to serve me. You will be my holy nation.' That is what you must tell the Israelites."
So Moses went back. He sent for the elders of the people. He explained to them everything the LORD had commanded him to say.
All of the people answered together. They said, "We will do everything the LORD has said." So Moses brought their answer back to the Lord.
The LORD spoke to Moses. He said, "I am going to come to you in a thick cloud. The people will hear me speaking with you. They will always put their trust in you." Then Moses told the LORD what the people had said.
The LORD said to Moses, "Go to the people. Today and tomorrow set them apart for me. Have them wash their clothes.
Have the people ready by the third day. On that day I will come down on Mount Sinai. Everyone will see it.
"Put limits for the people around the mountain. Tell them, 'Be careful that you do not go up the mountain. Do not even touch the foot of it. You can be sure that all who touch the mountain will be put to death.
Do not lay a hand on any of them. Kill them with stones or shoot them with arrows. Whether they are people or animals, do not let them live.' They may go up to the mountain only when the ram's horn gives out a long blast."
Moses went down the mountain to the people. After he set them apart for the Lord, they washed their clothes.
Then he spoke to the people. He said, "Get ready for the third day. Don't make love."
On the morning of the third day there was thunder and lightning. A thick cloud covered the mountain. A trumpet gave out a very loud blast. Everyone in the camp trembled with fear.
Then Moses led the people out of the camp to meet with God. They stood at the foot of the mountain.
Smoke covered Mount Sinai, because the LORD came down on it in fire. The smoke rose up from it like smoke from a furnace. The whole mountain trembled and shook.
The sound of the trumpet got louder and louder. Then Moses spoke. And the voice of God answered him.
The LORD came down to the top of Mount Sinai. He told Moses to come to the top of the mountain. So Moses went up.
The LORD said to him, "Go down and warn the people. They must not force their way through to see me. If they do, many of them will die.
The priests approach me when they serve me. But even they must set themselves apart for me. If they do not, my anger will break out against them."
Moses said to the Lord, "The people can't come up Mount Sinai. You yourself warned us. You said, 'Put limits around the mountain. Set it apart as holy.' "
The LORD replied, "Go down. Bring Aaron up with you. But the priests and the people must not force their way through. They must not come up to me. If they do, my anger will break out against them."
So Moses went down to the people and told them.