'Unclean' in the Bible

For they [the gifts, sacrifices, and ceremonies] deal only with [clean and unclean] food and drink and various ritual washings, [mere] external regulations for the body imposed [to help the worshipers] until the time of reformation [that is, the time of the new order when Christ will establish the reality of what these things foreshadow—a better covenant].

For if the blood of bulls and of goats, and the ashes of an heifer sprinkling the unclean, sanctifieth to the purifying of the flesh:

How much severer punishment do you think he will deserve who has trampled under foot the Son of God, and has regarded as unclean the blood of the covenant by which he was sanctified, and has insulted the Spirit of grace?

Looking with care to see that no man among you in his behaviour comes short of the grace of God; for fear that some bitter root may come up to be a trouble to you, and that some of you may be made unclean by it;

Let married life be honoured among all of you and not made unclean; for men untrue in married life will be judged by God.