Exodus 19:12

19:12 You must set boundaries for the people all around, saying, ‘Take heed to yourselves not to go up on the mountain nor touch its edge. Whoever touches the mountain will surely be put to death!

Joshua 3:4-5

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.”

3:5 Joshua told the people, “Ritually consecrate yourselves, for tomorrow the Lord will perform miraculous deeds among you.”