I have more than 25 Christmas carols that I want to post here, so I'm starting today instead of waiting until December. (For my non-Catholic friends -- Advent starts this Sunday.)

1
O come, O come, Emmanuel
And ransom captive Israel,
That mourns in lonely exile here,
Until the Son of God appear.
2
O come, thou Dayspring, come and cheer
Our spirits by thine advent here;
Disperse the gloomy clouds of night,
And death's dark shadows put to flight.
3
O come, thou Wisdom from on high,
And order all things, far and night;
To us the path of knowledge show,
And cause us in her ways to go.
4
O come, Desire of nations, bind
In one the hearts of all mankind;
Bid thou our sad divisions cease,
And be thyself our Prince of Peace.
REFRAIN
Rejoice! Rejoice! Emmanuel
Shall come to thee, O Israel!
Unknown Author, original text Latin, translated by John M. Neale (1851)
https://www.youtube.com/watch?v=7xtpJ4Q_Q-4&list=RD7xtpJ4Q_Q-4&start_radio=1
O Come Emmanuel has its roots in Latin, likely from a sixth-century evening prayer book known as O Antiphons which consisted of seven separate texts, each beginning with the vocative particle “O” followed by an attribute of Jesus. They were either sung or recited as part of an annual Christmas tradition, leading up to Christmas Eve. These texts include:
O Sapientia (O Wisdom)
O Adonai (O Lord)
O Radix Jesse (O Root of Jesse)
O Clavis David (O Key of David)
O Oriens (O Dayspring)
O Rex Gentium (O King of the Nations)
O Emmanuel (O God With Us)
This song is rife with scripture references, specifically Old Testament prophecies of the Messiah, and New Testament passages that reference Jesus as the fulfillment of those prophecies.
1
O COME O COME EMMANUEL Is 7:14 Matt 1:23
AND RANSOM CAPTIVE ISRAEL
THAT MOURNS IN LONELY EXILE HERE
UNTIL THE SON OF GOD APPEAR Is 35:10 Matt 1:21
Refrain:
REJOICE REJOICE EMMANUEL
SHALL COME TO THEE O ISRAEL Luke 2:10-12
2
O COME THOU ROD OF JESSE FREE Is 11:1-2 Matt 1:6-16 Luke 3:23-32
THINE OWN FROM SATAN'S TYRANNY Acts 10:38 1 Cor 10:13
FROM DEPTHS OF HELL THY PEOPLE SAVE
AND GIVE THEM VICTORY O'ER THE GRAVE Rom 8:37 1 Cor 15:54-57 Heb 2:14-15
3
O COME THOU DAYSPRING FROM ON HIGH Luke 1:78
AND CHEER US BY THY DRAWING NIGH
DISPERSE THE GLOOMY CLOUDS OF NIGHT
AND DEATH'S DARK SHADOWS PUT TO FLIGHT Is 9:2 John 1:1-8 John 8:12 Eph 5:14
4
O COME THOU KEY OF DAVID COME Rev 8:7
AND OPEN WIDE OUR HEAV'NLY HOME John 14:2
MAKE SAFE THE WAY THAT LEADS ON HIGH
AND CLOSE THE PATH TO MISERY John 14:6 Acts 4:12
5
O COME ADONAI LORD OF MIGHT Genesis 1:1, Deuteronomy 4:39, Deuteronomy 10:14, Joshua 2:11, Nehemiah 9:6, Psalm 29:10, Psalm 45:6, Psalm 50:7-15, Psalm 93:1-2, Psalm 115:3, Psalm 135:6, Isaiah 43:13, Isaiah 45:9-10, Isaiah 46:10, Lamentations 5:19, Daniel 4:35, Romans 9:19-21, Ephesians 1:11, Hebrews 1:8, James 4:15, Revelation 4:11, and Revelation 20:11
WHO TO THY TRIBES ON SINAI'S HEIGHT
IN ANCIENT TIMES DIDST GIVE THE LAW
IN CLOUD AND MAJESTY AND AWE Deut 27:12-13 Ex 19-23
6
O COME THOU WISDOM FROM ON HIGH 1 Cor 1:24
AND ORDER ALL THINGS FAR AND NIGH Jer 51-15
TO US THE PATH OF KNOWLEDGE SHOW
AND CAUSE US IN HER WAYS TO GO Proverbs 3:5-6, Matthew 7:13, and 1 Corinthians 10:13
7
O COME DESIRE OF NATIONS BIND Haggai 2:7
ALL PEOPLES IN ONE HEART AND MIND Rom 14:11 Phil 2:10-11
BID ENVY STRIFE AND QUARRELS CEASE
FILL THE WHOLE WORLD WITH HEAVEN'S PEACE Luke 2:13-14