Numbers 6:10-11

10On the eighth day they must bring two turtledoves or two young pigeons to the priest at the entrance of the Tabernacle.

11The priest will offer one of the birds for a sin offering and the other for a burnt offering. In this way, he will purify them from the guilt they incurred through contact with the dead body. Then they must reaffirm their commitment and let their hair begin to grow again.