The O Antiphons are a series of seven antiphons used in the Christian liturgy during the last days of Advent, from December 17 to December 23. Each antiphon begins with the exclamation "O" and addresses Christ with different titles, reflecting the messianic hopes of the Old Testament. Here are the seven O Antiphons:

December 17

O Sapientia (O Wisdom) - Isaiah 11:2-3

December 18

O Adonai (O Lord) - Exodus 3:14

December 19

O Radix Jesse (O Root of Jesse) - Isaiah 11:1

December 20

O Clavis David (O Key of David) - Isaiah 22:22

December 21

O Oriens (O Rising Sun) - Malachi 4:2

December 22

O Rex Gentium (O King of Nations) - Isaiah 9:6

December 23

O Emmanuel (O God with Us) - Isaiah 7:14