Baptism is one of the seven church sacraments we are reborn and enters into the Kingdom of God.
The Church can baptize any newborn child boy or girl on any day without waiting forty or eighty days if the life of the baby is in danger[Fetha Negest 3].
The forty or eighty day-waiting period is the required time before the mother is allowed to participate in her child’s baptism. For God commanded Moses saying, "If a woman has conceived, and borne a male child, then she shall be unclean seven days; as in the days of her customary impurity she shall be unclean. 'And on the eighth day the flesh of his foreskin shall be circumcised. 'She shall then continue in the blood of her purification thirty-three days. She shall not touch any hallowed thing, nor come into the sanctuary until the days of her purification are fulfilled. 'But if she bears a female child, then she shall be unclean two weeks, as in her customary impurity, and she shall continue in the blood of her purification sixty-six days" (Lev 12:2-5).
The Forty and eighty days also signifies that the first persons [Adam and Eve] obtained adoption from God. The Book of Jubilee 4:2-15 describe how our father Adam and Eve enter to heaven in their 40 and 80 days respectively after their creation with the Holy Angels accompanied them. Likewise, we enter to the church, which is the type of the heaven, to be members of the follow Saints and Angels and become son’s and daughter’s of God on 40 and 80 days depending on the gender.
Our Lord and Jesus Christ has also fulfilled what is described on the old testament literally. Circumcision in the old testament was practices as sign of baptism [in the New Testament Circumcision is replaced by Baptism to inherit the kingdom of God [Col 2:11]. The circumcised was considered a member of God's people according to the covenant between God and Abraham (Gen.17: 11). It is known that circumcision was to be done on the eighth day after birth, according to God's command (Gen.17: 12). Even our Lord has fulfilled this law [Lk 2:21]. “And when the day of purification according to the law of Moses were completed [ means after 40 days of His birth], [His parents] took Our lord to the temple”. [Lk 2:21-25].