The Byzantine Christmas Hymn “Today the Virgin gives birth to him who is beyond substance” by Romanos Melodos (The first three stanzas). Available also in the Greek original.

Today the Virgin gives birth to him who is beyond substance;
and the earth offers a cave to him who is unapproachable.
Angels with shepherds give praise,
and by a star the Wise Men make their way;
for unto us is born
a little child, God of all time.

Bethlehem has opened the gates of Eden; come, let us see.
In a secret place we have found delight; come, let us partake
of paradise within the cave.
In it has appeared a root never watered, blossoming forth forgiveness;
in it has been found a well never dug,
a well from which David once longed to drink.
In it a virgin has given birth to a child,
and at once has brought to an end the thirst of Adam and of David.
Therefore, let us hasten to the place where has been born
a little child, God of all time.