"Today has come the beginning of our salvation, O people..."

The Nativity of the Theotokos (source)

  
Today has come the beginning of our salvation, O people, for behold, she who was chosen beforehand from the ancient generations, the Mother and Virgin, and the container for God, comes forth to be born from a barren woman. O flower from the Root of Jesse, and his rod which sprouted forth. Rejoice, O Forefather Adam, and let Eve rejoice with gladness, for behold, she who was formed from the rib of Adam, the daughter and offspring, is blessed openly. For [Adam] says, "From me is born deliverance, from whom will come for me freedom from the bonds of Hades." Let David rejoice, striking the harp, and let him bless God, for behold, the Virgin comes forth from [a Mother] barren as stone, for the salvation of our souls.
-Idiomelon of the Litia in the First Tone, by Stephanos of the Holy City
  
(source)
  

Most-Holy Theotokos, save us!