Exodus 19:21-24

21The Lord said to Moses, ‘Go down to the people. Warn them that they must stay away from the mountain. They must not cross the line to try to see me, the Lord. If they do that, many of them will die.

22Even the priests must make themselves clean before they come near to me. If they do not obey this command, I will punish them. I am the Lord.’

23Moses said to the Lord, ‘The people cannot come up Sinai mountain. You warned us that we must make a line round the edge of the mountain. You said that we must make the mountain a special place.’

24The Lord replied, ‘Now go back down. Then bring Aaron up with you. But the priests and the people must stay where they are. They must not try to come up here where I am. If they come across the line, I will punish them.’