NUM 6:11

11 ‘The priest must [kill the birds and] offer them as sacrifices. One of them will be an offering to enable me to forgive you for the sins you have committed, and the other will be an offering that is burned completely to please me. [After the priest burns them on the altar], I will forgive you for having come close to a corpse, and [when] your hair [grows again it] will be dedicated to me again.