Synaxis of the Holy Theotokos
This Synaxis - which is to say, our coming together to glorify the Theotokos - is celebrated especially in her honour because she gave birth supernaturally to the Son and Word Of God, and thus became the instrument of the salvation of mankind.
Apolytikion of Synaxis of the Theotokos in the Fourth Tone
Thy Nativity, O Christ our God, hath shined the light of knowledge upon the world; for thereby they that worshipped the stars were instructed by a star to worship Thee, the Sun of Righteousness, and to know Thee, the Dayspring from on high. O Lord, glory be to Thee.
Kontakion of Synaxis of the Theotokos in the Plagal of the Second Tone
He, who was begotten of the Father before the morning star, without a mother, becomes incarnate of you today, without a father. Wherefore, a star announces the good news to the Magi. Angels with shepherds praise your immaculate birth-giving, O Full of Grace.