Leviticus 15:28-30
Purity Regulations from Female Bodily Discharges
15:28 “‘If she becomes clean from her discharge, then she is to count off for herself seven days, and afterward she will be clean.
15:29 Then on the eighth day she must take for herself two turtledoves or two young pigeons and she must bring them to the priest at the entrance of the Meeting Tent,
15:30 and the priest is to make one a sin offering and the other a burnt offering. So the priest is to make atonement for her before the Lord from her discharge of impurity.