Leviticus 5:18

He 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 .

They are to bring to the priest as a guilt offering a ram from the flock, one without defect and of the proper value. In this way the priest will make atonement for them for the wrong they have committed unintentionally, and they will be forgiven.

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.