Exodus 19:12-13

And let limits be marked out for the people round the mountain, and say to them, Take care not to go up the mountain or near the sides of it: whoever puts his foot on the mountain will certainly come to his death: He is not to be touched by a hand, but is to be stoned or have an arrow put through him; man or beast, he is to be put to death: at the long sounding of a horn they may come up to the mountain.