'Purify' in the Bible

Now the Passover of the Jews was near, and many went up to Jerusalem from the [surrounding] country before the Passover, so that they could purify themselves.

Take these [men] [and] purify yourself along with them and {pay their expenses} so that they can shave [their] heads, and everyone will know that [the things] which they had been informed about you are nothing, but you yourself also agree with observing the law.

who gave himself for us, in order that he might redeem us from all lawlessness and purify for himself a people for his own possession, zealous for good deeds.

Draw near to God, and he will draw near to you. Cleanse [your] hands, [you] sinners, and purify [your] hearts, [you] double-minded!