Peace to All,
It carries over from the Law of Moses and the period of "uncleanness" of the mother. It is not strict , but rather just traditional, and helps the health of the mother by giving her a period of rest before she returns to church.
This of course, is correct, but I would like to add that the tradition of Baptizing Males (40 Days) and Females (80 Days) on these specific days came from the tradition that: 'after God created Adam, Adam ascended into Paradise in glory 40 days after his birth (or, creation out of the four physical elements and three elements of the soul).' Eighty (80) days after Adam's ascension into Paradise, God caused him to be in a transic state (a state of sleep) and then God created Eve out of the side of Adam (this is the birth of Eve, from Adam).'
So, baptism is the re-birth of the person who receives it in faith.
This is according to my little knowledge. Therefore as Marc Hanna stated, the Mosaic Law incorporated these days as 'cleansing days' or 'new births'.
CATECHIZING nowadays varies. I understand that in the early Church, the Initiation of the the unbaptized (but learning) was like joining the imperial army, even much more concerning (of course), because once a person is baptized, he or she becomes a soldier in the heavenly army and is granted the most mysterious and precious helmet, shield, sword and armour--which comes from the Lord Himself. It is a crowning and the person who was a candidate for baptism treasured this reception of the most holy mysteries in his or heavenly heart.
Does one think if he or she enters the imperial army, they will be immediately granted a knife, gun or even protective clothin? Never. First they must prove themselves to the sergent or corporal that they are worthy to receive such precious tools and instruments. So, what about the eternal mysteries from the Father? Those mysteries that were paid for by the Father's only-begotten Son Jesus Christ?
Today, I personally have seen folks who want to be baptized on the spot, because they think that Orthodoxy is 'exotic' or receiving a baptismal name (a new name) is cool. Some want to be unique in their social communities, so they beg to baptized and unfortunately, some bishops and priests baptize them, believing they are doing a great thing (by gaining a new member) or even for money.
This deserves excommunication: earthly and heavenly.
In the days of old, some candidates had to study for years, before the Catechist would consider them for baptism (of course, this excludes emergency situations). This is how treasured the mysteries of Christ's Church were and are.
About Orthodox Marriages and the Fast Period:
I believe that St. John Chrysostom
commented on this, but for sure H.H. Pope Shenouda III
lectured and wrote also, saying something like this: It is ashame that nowadays, the candidates for marriage do not even fast like those in the olden days. They rather feast and entertain their guests instead of entertaining their Lord, who they receive during the Liturgical Ceremony...
I believe that the tradition of NOT GETTING MARRIED DURING THE FAST PERIOD was due to the weakness of what we consider mondernists. It is because most of us nowadays think about our carnal desires more than heavenly ones. Don't get me wrong, I'm not saying that there shouldn't be physical intimacy between the blessed couple, but without any doubt, the tradition of FEAST DAY & NON-FAST DAY MARRIAGES is motivated by pleasing our earthly guests.
Anyway, if anyone is reading, I apologize for rambling on...