Leviticus 12:7
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. 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.
The regulation belongs to the requirement that a mother pass through the appointed purification after giving birth to either a son or a daughter and present the prescribed sacrificial offerings. The prescribed offering was a lamb for a burnt offering together with a pigeon or turtledove for a sin offering, though parents who were poor might bring two birds instead of the lamb. Each offering was to be without blemish, and both pointed to Christ.
About forty days after the birth of Jesus, Mary and Joseph kept this requirement when they brought Him to Jerusalem. As the substitute for humanity, Christ in that presentation met the law in every detail. His flawless physical condition marked Him as the unblemished offering and as the pattern of humanity as God intended it to be, living in obedience to divine law.