The Third Sunday in Advent, Gaudete Sunday.
"Gaudete" comes from the Latin Antiphon, which begins, "Gaudete in Domino semper: iterum dico, gaudete.." [Rejoice in the Lord always, again I say, rejoice...]. On this day, rose-colored vestments are worn, and flowers may decorate the chancel of the church.
Father of our Lord Jesus Christ,
ever faithful to your promises
and ever close to your Church:
the earth rejoices in hope of the Savior's coming
and looks forward with longing
to his return at the end of time.
Prepare our hearts and remove the sadness
that hinders us from feeling the joy and hope
which his presence will bestow,
for he is Lord for ever and ever.
The Opening Mass Prayer for the Third Sunday of Advent
From the Companion Missal