Exodus 19:20-25

20And Jehovah came down on mount Sinai, on the top of the mountain; and Jehovah called Moses to the top of the mountain, and Moses went up. 21And Jehovah said to Moses, Go down, testify to the people that they break not through to Jehovah to gaze, and many of them perish. 22And the priests also, who come near to Jehovah, shall hallow themselves, lest Jehovah break forth on them. 23And Moses said to Jehovah, The people cannot come up to mount Sinai; for thou hast testified to us, saying, Set bounds about the mountain, and hallow it. 24And Jehovah said to him, Go, descend, and thou shalt come up, thou, and Aaron with thee; but the priests and the people shall not break through to go up to Jehovah, lest he break forth on them. 25So Moses went down to the people, and told them.