Exodus 19:23

Moses said to the LORD, "The people can't come up to Mount Sinai, for you warned us, saying, 'Set bounds around the mountain, and sanctify it.'"

Exodus 19:12

You shall set bounds to the people all around, saying, 'Be careful that you do not go up onto the mountain, or touch its border. Whoever touches the mountain shall be surely put to death.

Joshua 3:4-5

Yet there shall be a space between you and it, about two thousand cubits by measure. Do not come near to it, that you may know the way by which you must go; for you have not passed this way before."

Treasury of Scripture Knowledge

Summary

And Moses said unto the LORD, The people cannot come up to mount Sinai: for thou chargedst us, saying, Set bounds about the mount, and sanctify it.

Bible References

Set bounds

Exodus 19:12
You shall set bounds to the people all around, saying, 'Be careful that you do not go up onto the mountain, or touch its border. Whoever touches the mountain shall be surely put to death.
Joshua 3:4
Yet there shall be a space between you and it, about two thousand cubits by measure. Do not come near to it, that you may know the way by which you must go; for you have not passed this way before."