Exodus 19:11-13

11and have them ready for the third day, for on 1the third day the Lord will come down on Mount Sinai in the sight of all the people.

12But you shall set boundaries for the people all around, saying, ‘2Beware that you do not go up on the mountain or touch the border of it; 3whoever touches the mountain shall certainly be put to death.

13No hand shall touch him, but 4he shall certainly be stoned or 5shot through; whether animal or person, the violator shall not live.’ When the ram’s horn sounds a long blast, they shall come up to 6the mountain.”