'Priests' in the Bible

and ye shall be unto me a kingdom of priests, and a holy nation. These are the words which thou shalt speak unto the children of Israel.

And let the priests also, that come near to Jehovah, sanctify themselves, lest Jehovah break forth upon them.

And Jehovah said unto him, Go, 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 Jehovah, lest he break forth upon them.