Leviticus 5:6-7

⁶And he shall bring his trespass-offering unto the Lord for his sin which he hath committed, a female from the flocks, a sheep or a goat, for a sin-offering; and the priest shall make an atonement for him concerning his sin.

⁷And if his means be not sufficient for a sheep, then shall he bring as his offering for the trespass which he hath committed, two turtle-doves, or two young pigeons, unto the Lord; one for a sin-offering, and the other for a burnt-offering.