On the second day of the Feast of the Nativity of our Lord Jesus Christ, the Church has established the celebration of the Synaxis of the Most Holy Mother of God. The name of today's festival signifies the gathering of the faithful in order to praise and glorify the most holy Virgin, who gave birth to our Savior.
On the first day of the Nativity of the Lord, the Church glorifies the Redeemer of the human race, and the blessed deliverance which freed the sinful world from the slavery to the Enemy. On the second day of the Nativity of the Lord, which was such a great event for our salvation, the Church calls upon us to honor the Ever-Virgin Mary, the Mother of our Lord, in an appropriate manner.
The day after many of the Church's Feast Days is called the Synaxis - such as the day after the Nativity of the Theotokos, when the righteous Joachim and Anna are commemorated; or the day following the Feast of Theophany, when we honor Saint John the Baptist, etc.
The Feast of the Synaxis of the Mother of God dates back to very ancient times. In the IV century, some Holy Fathers, such as Saint Epiphanios of Cyprus, were already preaching about it.
This feast used to be called "the Nativity Gifts." This refers to the gifts which the Magi from the East brought to the newborn King of the Jews - the Divine Child Jesus. The Feast of the Synaxis of the Mother of God was also called "the Flight into Egypt."
On December 26, the early Church commemorated the Wise Men who came to worship the Savior, and the flight into Egypt, as well as the Synaxis of the Mother of God. That is why some icons of the Nativity of the Lord depict His Birth, the worship of the shepherds and the Magi, as well as the Flight into Egypt.
O Most Pure Mother of God,
your holy Synaxis is adorned with many diverse splendors;
and gifts are brought to you by many peoples of the world, O Lady Theotokos.
In your mercy, loosen the bonds of our sinfulness, and save our souls.
He Who was begotten before the morning star by the Father without a mother
is incarnate of you today on earth without a father.
Therefore, a star announces the glad tidings to the Magi,
while Angels and shepherds sing of your undefiled child-bearing,
O full of grace.