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).