Leviticus 5:2; Leviticus 5:11

2 “ ‘If anyone becomes aware that they are guilty—if they unwittingly touch anything ceremonially unclean (whether the carcass of an unclean animal, wild or domestic, or of any unclean creature that moves along the ground) and they are unaware that they have become unclean, but then they come to realize their guilt;

11 “ ‘If, however, they cannot afford two doves or two young pigeons, they are to bring as an offering for their sin a tenth of an ephah of the finest flour for a sin offering. They must not put olive oil or incense on it, because it is a sin offering.