to make a distinction between holy and unholy, and between unclean and clean,

Therefore thus says Jehovah, If you turn back, then I will bring you back again; you shall stand before Me. And if you take the precious out from the vile, you shall be as My mouth. Let them turn back to you, but do not return to them.

And they shall teach My people the difference between the holy and the profane, and cause them to discern between the unclean and the clean.

Take heed regarding the plague of leprosy, that you take great heed to do according to all that the priests, the Levites, shall teach you; as I have commanded them, thus you shall take heed to do.