Leviticus 14:57
to teach when there is uncleanness, and when it is purified: this is the law of leprosy.
Leviticus 10:10
that ye may put difference between the holy and the unholy, and between unclean and clean,
Deuteronomy 24:8
Take heed in the plague of leprosy, that thou take great heed, and do according to all that the priests the Levites shall teach you: as I commanded them shall ye take heed to do.
Jeremiah 15:19
Therefore thus saith Jehovah: If thou return, then will I bring thee again, thou shalt stand before me; and if thou take forth the precious from the vile, thou shalt be as my mouth. Let them return unto thee; but return not thou unto them.
Ezekiel 44:23
And they shall teach my people the difference between holy and profane, and cause them to discern between unclean and clean.