From the Principal Service Old Testament reading:

See, I am sending my messenger to prepare the way before me, and the Lord whom you seek will suddenly come to his temple. The messenger of the covenant in whom you delight – indeed, he is coming, says the Lord of hosts.
But who can endure the day of his coming, and who can stand when he appears?
For he is like a refiner’s fire and like fullers’ soap; he will sit as a refiner and purifier of silver, and he will purify the descendants of Levi.
(Malachi, Chapter 3, verses 1-3, NRSV)

And from the Gospel:

The word of God came to John son of Zechariah in the wilderness.
He went into all the region around the Jordan, proclaiming a baptism of repentance for the forgiveness of sins, as it is written in the book of the words of the prophet Isaiah,
‘The voice of one crying out in the wilderness:
“Prepare the way of the Lord,
make his paths straight.
(Luke’s Gospel, chapter 3, verses 2-4, NRSV)

I defy anyone not be be humming The Messiah already…

This window is in the chapel of Peterhouse College, Cambridge