Exodus 19:21

19:21 The Lord said to Moses, “Go down and solemnly warn the people, lest they force their way through to the Lord to look, and many of them perish.

Exodus 19:24

19:24 The Lord said to him, “Go, get down, and come up, and Aaron with you, but do not let the priests and the people force their way through to come up to the Lord, lest he break through against them.”