Leviticus 5:2-3

“ ‘Or someone might touch something unclean, such as the dead body of an unclean wild animal or an unclean farm animal or an unclean crawling animal. Even if he does not know that he touched it, he will still be unclean and guilty of sin. “ ‘Someone might touch human uncleanness—anything that makes someone unclean—and not know it. But when he learns about it, he will be guilty.