Leviticus 5:2-7

2Or if a person touches 1any unclean thing, whether a carcass of an unclean animal, or the carcass of unclean cattle, or a carcass of unclean swarming things, though it is hidden from him and he is unclean, then he will be guilty. 3Or if he touches human uncleanness, of whatever sort his uncleanness may be with which he becomes unclean, and it is hidden from him, and then he comes to know it, he will be guilty. 4Or if a person 2swears thoughtlessly with his lips to do evil or to do good, in whatever matter people speak thoughtlessly with an oath, and it is hidden from him, and then he comes to know it, he will be guilty of one of these things. 5So it shall be when he becomes guilty of one of these things, that he shall 3confess that in which he has sinned. 6He shall also bring his guilt offering to the Lord for his sin which he has 4committed, 5a female from the flock, a lamb or a 6goat as a sin offering. So the priest shall make atonement on his behalf for his sin.

7‘But if 7he cannot afford a lamb, then he shall bring to the Lord his guilt offering for that in which he has sinned, two turtledoves or two young doves, 8one as a sin offering and the other as a burnt offering.