On this day the church celebrates the entrance of the Theotokos (the Mother of God) into the temple in Jerusalem. Like the stories about the birth of the Mother of God, celebrated on September 8th, the feast is not found in the Bible but is part of the non-biblical tradition, primarily the Protoevangelium of James.
This feast tells us that Joachim and Anna, the parents of the Theotokos, were elderly and childless. They prayed for a child and promised that when a child was born they would dedicate it to God. So when Mary was born they brought her to the temple to live a life dedicated to God. Her family and friends accompanied her to the temple carrying candles and singing. As they led her to the temple they sang verses from psalm 45:
Hear, O daughter, consider, and incline your ear; forget your people and your father’s house;  and the king will desire your beauty. Since he is your lord, bow to him;  the people of Tyre will sue your favor with gifts, the richest of the people  with all kinds of wealth. The princess is decked in her chamber with gold-woven robes;  in many-colored robes she is led to the king, with her virgin companions, her escort, in her train.  With joy and gladness they are led along as they enter the palace of the king.  Instead of your fathers shall be your sons; you will make them princes in all the earth.  I will cause your name to be celebrated in all generations; therefore the peoples will praise you for ever and ever.
The Orthodox Church considers this psalm as prophecy of Mary the Theotokos. The tradition tells us that when the Theotokos got to the temple, the high priest led her nto the Holy of Holies, where the High Priest himself could only enter once a year.
The historian Josephus, tells us that there were living quarters for women near the temple and tradition tells us that Mary lived in a community of virgins. She read and listened to Holy Scripture, occupied herself with handicrafts and prayed. She led a life dedicated to God from her earliest years.
Again, all of this comes from extra-biblical tradition. However, the theological point is quite clear, that Mary the Theotokos is now the living temple. The temple had always been considered the place of God’s presence on earth and now Mary has become the dwelling place of God. Now all the Old Testament prophecies which talk about the “dwelling of God is with man” are fulfilled and that the human person is the dwelling place of God.
At the vigil of the feast, three sections of the Old Testament are read. All of these readings end with the same verse, “for the glory of the Lord filled the house of the Lord God almighty” (Exodus 40:35, I Kings 8:11, Ezekiel 44:4). And the feast tells us something about ourselves also, by virtue of our baptism and our receiving our Lord’s Body and Blood in Holy Communion. As Saint Paul writes “What agreement has the temple of God with idols? For we are the temple of the living God; as God said, “I will live in them and move among them, and I will be their God, and they shall be my people.” (II Cor 6:16). The Old Testament readings are considered to be symbols of the Mother of God. The “glory of the Lord” is present in the Theotokos, it fills her and all those who “hear the word of God and keep it” (Lk 11:27-28). The epistle reading for he Divine Liturgy (Heb 9:1-7) tells us the same thing.
Note – much of our information about the life of the Theotokos is found in a book called the Protoevangelion (or Protoevangelium) of James. This book tells us about the birth of the Mother of God, her childhood and the birth of Jesus. Some may be tempted to dismiss this book and its stories, but actually it is dated rather early, from about 150 AD, and scholars believe that it contains a much earlier Christian tradition which had been passed down orally for several generations. So we cannot ‘prove’ that this book is true, but its use in the theology and liturgy of the Church shows us its importance.
The Entry of the Theotokos into the Temple
Troparion — Tone 4
Today is the prelude of the good will of God, of the preaching of the salvation of mankind. The Virgin appears in the temple of God, in anticipation proclaiming Christ to all. Let us rejoice and sing to her: “Rejoice, O Fulfillment of the Creator’s dispensation.”
Kontakion — Tone 4
The most pure Temple of the Savior; the precious Chamber and Virgin; the sacred Treasure of the glory of God, is presented today to the house of the Lord. She brings with her the grace of the Spirit, therefore, the angels of God praise her: “Truly this woman is the abode of heaven.”