Leviticus 5:7

5:7 “‘If he cannot afford an animal from the flock, he must bring his penalty for guilt for his sin that he has committed, two turtledoves or two young pigeons, to the Lord, one for a sin offering and one for a burnt offering.

Leviticus 5:9-10

5:9 Then he must sprinkle some of the blood of the sin offering on the wall of the altar, and the remainder of the blood must be squeezed out at the base of the altar – it is a sin offering. 5:10 The second bird he must make a burnt offering according to the standard regulation. So the priest will make atonement on behalf of this person for his sin which he has committed, and he will be forgiven.