At Vespers on these days, we pray one of the "O" antiphons at the Magnificat. Today, December 23, the antiphon is "O Emmanuel":
O Emmanuel, Rex et légifer noster, exspectátio Géntium, et Salvátor eárum: veni ad salvándum nos, Dómine Deus noster.
O Emmanuel, King and Lawgiver, the one longed for by the nations, their Savior; come and save us, Lord our God.
In her last great invocation to the King-Messiah, the Church calls Him by the greatest and holiest of His titles: Emmanuel, God with us. Looking to the throne of the Most High, she acknowledges His eternal royalty and infinite dominion. With adoration, humility, and confidence she pleads for His coming.
As we go about our final preparations fo the visit of our divine Lord, let us repeat often in the depths of our soul His name: Emmanuel. Only by continual and reverent meditation upon His glorious title can we grasp its significance: God with us. To redeem our wretchedness and purchase forgiveness of our sins, the eternal Son of God becomes out brother, clothes Himself in our nature, assumes the pains, humiliations, and necessities of our humanity.