On this day the Virgin gives birth to the Super-essential. Η Παρθένος Σήμερον.

“On this day the Virgin gives birth to the Super-essential. To the Unapproachable, earth is providing the grotto. Angels sing and with the shepherds offer up glory. Following a star the Magi are still proceeding. He was born for our salvation, a newborn Child, the pre-eternal God.”
Kontakion of Nativity

Σήμερον.