Exodus 19:22-24

22And let the priests also, which come near to the Lord, sanctify themselves, lest the Lord break forth upon them.

23And 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.

24And the Lord said unto him, Away, get thee down, and thou shalt come up, thou, and Aaron with thee: but let not the priests and the people break through to come up unto the Lord, lest he break forth upon them.