Advent Ember Days

As this site reminds us:

Wednesday, Friday, and Saturday after Gaudete Sunday (3rd Sunday of Advent) are known as "Advent Embertide," and they come near the beginning of the Season of Winter (December, January, February). Liturgically, the readings for the days' Masses follow along with the general themes of Advent, opening up with Wednesday's Introit of Isaias 45: 8 and Psalm 18:2 :

Drop down dew, ye heavens, from above, and let the clouds rain the Just: let the earth be opened and bud forth a Savior. The heavens show forth the glory of God: and the firmament declareth the work of His hands.

Wednesday's and Saturday's Masses will include one and four Lessons, respectively, with all of them concerning the words of the Prophet Isaias except for the last lesson on Saturday, which comes from Daniel and recounts how Sidrach, Misach, and Abdenago are saved from King Nabuchodonosor's fiery furnace by an angel. This account, which is followed by a glorious hymn, is common to all Embertide Saturdays but for Whit Embertide.

The Gospel readings for the three days concern, respectively, the Annunciation (Luke 1:26-28), Visitation (Luke 1:37-47), and St. John the Baptist's exhorting us to "prepare the way of the Lord and make straight His paths" (Luke 3:1-6).

 

The Rorate Caeli performed above at Hereford Cathedral is from William Byrd's Gradualia:

 

℣ Rorate coeli desuper et nubes pluant justum
(Drop down dew, ye heavens, from above, and let the clouds rain the just)
℟ Aperiatur terra et germinet salvatorem"
(Let the earth be opened and send forth a Saviour").

 

Ps. Benedixisti, Domine, terram tuam: avertisti captivitatem Iacob

O Lord thou hast blessed thy land: thou hast turned away the captivity of Jacob.

Gloria Patri, et Filio, et Spiritui Sancto . . .
Glory to the Father, and to the Son, and to the Holy Spirit . . .

 

It is part of a Votive Mass for Our Lady during Advent and you may find the sheet music here.