Leviticus 5:3

“Or if he touch the uncleanness of man, etc.] The dead body of a man, or the bone of a dead body, or a grave, or any profluvious or menstruous person: whatsoever uncleanness [it be] that a man shall be defiled withal: not morally, but ceremonially: and it be hid from him; he is not sensible that he has touched any thing ceremonially unclean: when he knoweth [of it], then he shall be guilty: acknowledge his guilt, and offer a sacrifice for it, as after directed.”

“Special occasions are mentioned on which sin-offerings are to be made with a particular confession of the offence for which atonement is sought Leviticus 5:5. Leviticus 5:1 Swearing - Adjuration. The case appears to be that of one who has been put upon his oath as a witness by a magistrate, and fails to utter all he has seen and heard (compare the marginal references. and Proverbs 29:24; Numbers 5:21). Leviticus 5:2-3 Hid from him - Either through forgetfulness or indifference, so that purification had been neglected. In such a case there had been a guilty negligence, and a sin-offering was required. On the essential connection between impurity and the sin-offering, see Leviticus 12:1.…”

“When he knoweth - As soon as he knoweth it, he must not delay to make his peace with God. Otherwise he shall be guilty - For his violation and contempt of God's authority and command. Leviticus 5:4”

“5:3 Any bodily discharge, even blood, would render a person temporarily unclean (chs 11–15). The uncleanness itself was not sin, but it was a sin to neglect the uncleanness, allowing it to spread. Once people became aware of their unclean state, they were guilty if they neglected it.”

“the uncleanness: Lev. 12:1-13:59, 15:1-33, Lev 22:4-6; Num 19:11-16 Leviticus 5:4”