December 17 marks the beginning of the "O" Antiphons an ancient part of our liturgy, dating back to the fourth century, one for each day until Christmas Eve. These antiphons address Christ with seven magnificent Messianic titles, based on the Old Testament prophecies and types of Christ. The Church recalls the variety of the ills of man before the coming of the Redeemer. The antiphons beg God with mounting impatience to come and save His people. The order of the antiphons climbs climatically through our history of Redemption.

In the first, O Sapientia, we take a backward flight into the recesses of eternity to address Wisdom, the Word of God. In the second, O Adonai, we have leaped from eternity to the time of Moses and the Law of Moses (about 1400 B.C.). In the third, O Radix Jesse, we have come to the time when God was preparing the line of David (about 1100 B.C.). In the fourth, O Clavis David, we have come to the year 1000. In the fifth, O Oriens we see that the line of David is elevated so that the people may look on a rising star in the east, and hence in the sixth, O Rex Gentium, we know that He is king of all the world of man. This brings us to the evening before the vigil, and before coming to the town limits of Bethlehem, we salute Him with the last Great O, O Emmanuel, God-with-us —He Cometh.

• Sapientia or O Wisdom (December 17), O Wisdom (Sirach 24:3), Come and teach us the way of prudence (Isaiah 40:14).

• Adonai or O Lord and Ruler (December 18), O Adonai (Ex 3:14), Come, and with an outstretched arm redeem us (Jeremiah 32:21).

• Radix Jesse or O Root of Jesse (December 19), O Root of Jesse, (Isaiah 11:1), Come, save us, and do not delay (Habakkuk 2:3).

• Clavis David or O Key of David (December 20), Scepter of the house of Israel (Numbers 24:17): Come, and deliver him from the chains of prison who sits in darkness and the shadow of death (Ps 107:10).

• Oriens or O Rising Dawn or Morning Star (December 21), O Rising Dawn, (Jer 23:5), Come, and enlighten those who sit in darkness and in the shadow of death (Ps 107:10; Lk 1:78).

• Rex Gentium or O King of the Nations (December 22), O King of the Gentiles (Jeremiah 10:7), Come and save man whom You fashioned out of clay (Genesis 2:7).

• Emmanuel (December 23), O Emmanuel (Isaiah 7:14; 8:8; Luke 1:31-33), Come, and save us, O Lord our God.