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 19:23

19:23 Moses said to the Lord, “The people are not able to come up to Mount Sinai, because you solemnly warned us, ‘Set boundaries for the mountain and set it apart.’”