'Priests' in the Bible

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

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

And 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.