'Purify' in the Bible

Who understandeth his errors? Purify me from secret faults.

Purify me with hyssop, and I will be clean;wash me, and I will be whiter than snow.

For you, God, tested us, to purify us like fine silver.

Did I purify my heartand wash my hands in innocence for nothing?

Beth. With what doth a young man purify his path? To observe -- according to Thy word.