The Bible – Old Testament
The LORD said to Moses,
1 “Tell the Israelites: When a woman has conceived and gives birth to a boy, she shall be unclean for seven days, with the same uncleanness as at her menstrual period.
On the eighth day, the flesh of the boy’s foreskin shall be circumcised,
and then she shall spend thirty-three days more in becoming purified of her blood; she shall not touch anything sacred nor enter the sanctuary till the days of her purification are fulfilled.
If she gives birth to a girl, for fourteen days she shall be as unclean as at her menstruation, after which she shall spend sixty-six days in becoming purified of her blood.
“When the days of her purification for a son or for a daughter are fulfilled, she shall bring to the priest at the entrance of the meeting tent a yearling lamb for a holocaust and a pigeon or a turtledove for a sin offering.
The priest shall offer them up before the LORD to make atonement for her, and thus she will be clean again after her flow of blood. Such is the law for the woman who gives birth to a boy or a girl child.
2 If, however, she cannot afford a lamb, she may take two turtledoves or two pigeons, the one for a holocaust and the other for a sin offering. The priest shall make atonement for her, and thus she will again be clean.”
1 [2-3] The uncleanness of the woman was more serious during the first period, the seven days after the birth of a boy or the fourteen days after the birth of a girl; only during this period would the rules given in ⇒ Lev 15:19-24 apply.
2  Forty days after the birth of Jesus, his Virgin Mother made this offering of the poor (⇒ Luke 2:22, ⇒ 24); since the holocaust was offered in thanksgiving for the birth of the child, this was most fittingly offered by Mary. However, because of her miraculous delivery, she was not really obliged to make the sin offering of purification.