Ver. 30-31. And the priest shall take of the blood So that all the preceding actions, the bringing the offering, the putting the hand upon the head of it, and slaying it, were done by the man that sinned; of this and what follows here and in the next verse ( Leviticus 4:31 ) , (See Gill on Leviticus 4:25) (See Gill on Leviticus 4:26).
or if someone informs him about the sin he has committed, then he is to bring an unblemished female goat as his offering for the sin that he has committed.
He is to lay his hand on the head of the sin offering and slaughter it at the place of the burnt offering.
Then the priest must take some of its blood with his finger and apply it to the horns of the altar of burnt offering. He must pour out the rest of its blood at the base of the altar.
He is to remove all its fat just as the fat is removed from the fellowship sacrifice. The priest is to burn [it] on the altar as a pleasing aroma to the Lord. In this way the priest will make atonement on his behalf, and he will be forgiven.
"Or if the offering that he brings as a sin offering is a lamb, he is to bring an unblemished female.