Luke 2:24

And to offer a sacrifice according to that which is said in the law of the Lord, A pair of turtledoves, or two young pigeons.

Cross-reference

Leviticus 12:2 establishes the purification period after childbirth — the law that Mary fulfills by offering the sacrifice in Luke.

Leviticus 12:6-8 prescribes the purification offering — Mary's pair of turtledoves fulfills the provision for the poor.

Leviticus 12:8 is the exact law Mary follows — the provision for a poor woman's purification offering after childbirth.