Leviticus 5:1-2

MSB(i) 1 “If someone sins by failing to testify when he hears a public charge about something he has witnessed, whether he has seen it or learned of it, he shall bear the iniquity. 2 Or if a person touches anything unclean—whether the carcass of any unclean wild animal or livestock or crawling creature—even if he is unaware of it, he is unclean and guilty.