"The Bible is a book that has been read more and examined less than any book that ever existed." -- Thomas PaineThe Setup
As always, to set this up, God, literally God, the perfect being, is dictating to Moses about what a woman needs to do after giving birth. He has given instructions on circumcisions and spoken how the woman needs to purify herself...
And when the days of her purifying are fulfilled, for a son, or for a daughter, she shall bring a lamb of the first year for a burnt offering, and a young pigeon, or dove, for a sin offering, unto the door of the tabernacle of the congregation, unto the priest: Who shall offer it before the LORD, and make an atonement for her; and she shall be cleansed from the issue of her blood. This is the law for her that hath born a male or a female. And if she be not able to bring a lamb, then she shall bring two turtles, or two young pigeons; the one for the burnt offering, and the other for a sin offering: and the priest shall make an atonement for her, and she shall be clean. (Leviticus 12:6-8)The "Moral" of the Passage
The moral of this story is that God expects animal sacrifices. God, the perfect being, is pleased when an animal is killed and specifically what kind of animal. God's personal preference is a burnt lamb and pigeon/dove; however, God is not intransigent. If you can't manage his favorite, the second on his list are two turtles or two pigeons. God makes it quite clear that if you kill these animals for him, the woman will then be "clean."