Leviticus 5:17-19

And if a soul sin, and commit any of these things which are forbidden to be done by the commandments of the LORD; though he wist it not, yet is he guilty, and shall bear his iniquity. And he shall bring a ram without blemish out of the flock, with thy estimation, for a trespass offering, unto the priest: and the priest shall make an atonement for him concerning his ignorance wherein he erred and wist it not, and it shall be forgiven him. It is a trespass offering: he hath certainly trespassed against the LORD.