Exodus 19:20-24

Then the Lord came down on Mount Sinai, to the top of the mountain; and the Lord called Moses to the top of the mountain, and Moses went up.

Then the Lord spoke to Moses: “Go down, warn the people, so that they do not break through to the Lord to stare, and many of them perish.

Also have the priests who approach the Lord consecrate themselves, or else the Lord will break out against them.”

And Moses said to the Lord, “The people cannot come up to Mount Sinai, for You warned us, saying, ‘Set boundaries around the mountain and consecrate it.’ ”

Then the Lord said to him, “Go down and come up again, you and Aaron with you; but do not let the priests and the people break through to come up to the Lord, or He will break out against them.”