Leviticus 5:7-10

7“But if he cannot afford a lamb, then he shall bring to the LORD as his compensation for the sin that he has committed two turtledoves or two pigeons, one for a sin offering and the other for a burnt offering. 8He shall bring them to the priest, who shall offer first the one for the sin offering. He shall wring its head from its neck but shall not sever it completely, 9and he shall sprinkle some of the blood of the sin offering on the side of the altar, while the rest of the blood shall be drained out at the base of the altar; it is a sin offering. 10Then he shall offer the second for a burnt offering according to the rule. And the priest shall make atonement for him for the sin that he has committed, and he shall be forgiven.