Exodus 19:12; Exodus 19:13

12 Mark a boundary around the mountain that the people must not cross, and tell them not to go up the mountain or even get near it. If any of you set foot on it, you are to be put to death;

13 you must either be stoned or shot with arrows, without anyone touching you. This applies to both people and animals; they must be put to death. But when the trumpet is blown, then the people are to go up to the mountain."