Leviticus 5:17-19

17"If anyone sins, doing any of the things that by the Lord's commandments ought not to be done, though he did not know it, then realizes his guilt, he shall bear his iniquity.

18He shall bring to the priest a ram without blemish out of the flock, or its equivalent, for a guilt offering, and the priest shall make atonement for him for the mistake that he made unintentionally, and he shall be forgiven.

19It is a guilt offering; he has indeed incurred guilt before the Lord."