Exodus 19:10

6 And unto Me you shall be a kingdom of priests and a holy nation.’ These are the words that you are to speak to the Israelites.”

7 So Moses went back and summoned the elders of the people and set before them all these words that the LORD had commanded him.

8 And all the people answered together, “We will do everything that the LORD has spoken.” So Moses brought their words back to the LORD.

9 The LORD said to Moses, “Behold, I will come to you in a dense cloud, so that the people will hear when I speak with you, and they will always put their trust in you.” And Moses relayed to the LORD what the people had said.

10 Then the LORD said to Moses, “Go to the people and consecrate them today and tomorrow. They must wash their clothes

11 and be prepared by the third day, for on the third day the LORD will come down on Mount Sinai in the sight of all the people.

12 And you are to set up a boundary for the people around the mountain and tell them, ‘Be careful not to go up on the mountain or touch its base. Whoever touches the mountain shall surely be put to death.

13 No hand shall touch him, but he shall surely be stoned or shot with arrows—whether man or beast, he must not live.’ Only when the ram’s horn sounds a long blast may they approach the mountain.”

14 When Moses came down from the mountain to the people, he consecrated them, and they washed their clothes.

Read all of Exodus 19