Today, December 17, begins a final phase in Advent, when the zeal and intensity of the preparation deepens. This evening sees the first of the 'O' Antiphons which express the profound longing of the Church calling on the Savior to come. As part of Vespers, or the evening part of the Divine Office, men and women throughout the Church recite or sing the Magnificat, Mary's song of praise as recorded in the Gospel of St. Luke. The Magnificat begins and ends with an antiphon -- a verse or line, often from Scripture, that is usually related to the specific character of that day's feast. The 'O' antiphons are those antiphons before and after the Magnificat on the last seven evenings before Christmas.
The antiphon for this evening, Dec. 17, is "O Sapientia"
O Sapientia, quae ex ore Altissimi prodiisti, attingens a fine usque ad finem, fortiter suaviterque disponens omnia: veni ad docendum nos viam prudentiae
- O Wisdom, coming forth from the mouth of the Most High, reaching from one end to the other, mightily and sweetly ordering all things: Come and teach us the way of prudence.
Tonight we address Christ as Wisdom, the Wisdom that is spoken by the mouth of the Father.
After a quick search, I found this flashmob version of a polyphonic arrangement of "O Sapientia" by Bob Chilcott.