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.’”

Joshua 3:4

3:4 But stay about three thousand feet behind it. Keep your distance so you can see which way you should go, for you have not traveled this way before.”