Ezekiel 44:23

They shall teach; by their place they were bound to instruct the people, Leviticus 10:10,11; this was part of their work, to read the law, expound it, and resolve questions arising about it. They were to be, as ministers ought now to be, apt to teach, 1 Timothy 3:2. Between the holy and profane; whether legally and ceremonially so, or morally and really so, that they might keep the people from pollutions. Between the unclean and the clean; the same thing in other words, only this seems to require priests patient instructing, till the people have learned to difference unclean and clean.