Exodus 19:21-24

21And the LORD said to Moses, Go down, charge the people, lest they break through to the LORD to gaze, and many of them perish.1 22And let the priests also, who come near to the LORD, sanctify themselves, lest the LORD break forth upon them. 23And Moses said to the LORD, The people cannot come up to mount Sinai: for thou didst charge us, saying, Set bounds about the mount, and sanctify it. 24And the LORD said to him, Away, go down, and thou shalt come up, thou, and Aaron with thee: but let not the priests and the people break through to come up to the LORD, lest he break forth upon them.