'Be Clean' in the Bible

May a man be upright before God? or a man be clean before his Maker?

What is man, that he should be clean? and he which is born of a woman, that he should be righteous?

How then can man be justified with God? or how can he be clean that is born of a woman?

then shall I sow, and another eat; yea, my generation and posterity shall be clean rooted out.

For thou saidst, What advantage will it be unto thee? and, What profit shall I have, if I be cleansed from my sin?