I had a question regarding the wait after birth for women. I know for baby boys, it is 40 days and for baby girls, 80 days. But, if we are no longer following Moses' law, then why are we still following this rule?
For example men don't need to be circumcised to become Christian. So, why do we follow the old rules in some occasions and in some other cases, we don't?
Circumcision of the foreskin is no longer the seal of faith, which was according to the Law of Moses because the holy sacrament of baptism is exceedingly more superior and has replaced it.
"In Him you were also circumcised with the circumcision made without hands, by putting off the body of the sins of the flesh, by the circumcision of Christ, buried with Him in baptism, in which you also were raised with Him through faith in the working of God, who raised Him from the dead" (2 Colossians 2:11-12).
According to the Holy Book of Leviticus 12:1-5, the doubled waiting period is required for a female child. Forty days is generally sufficient for postpartum hemorrhaging to completely end, thus, allowing the mother to participate in her child's baptism. The doubled time for a female is a reminder that the woman was first tempted, and subsequently, sin entered into the world (1 Timothy 2:13-15; 1 Peter 3:7).
As Orthodox Christians, we have not simply abolished all former rules. We certainly still observe customs and teachings relevant to our salvation, such as the Ten Commandments.