'Unclean' in the Bible

Then said Haggai, If one that is unclean by reason of a dead body touch any of these, shall it be unclean? And the priests answered and said, It shall be unclean.

Then answered Haggai and said, So is this people, and so is this nation before me, saith Jehovah; and so is every work of their hands; and that which they offer there is unclean.