A reader writes:
I noticed our priest started wearing purple vestments on the first Sunday of Advent. Aren't purple vestments usually worn during Lent? At Christmas time, I would have expected something more festive, like red or green or white.
You're very observant! You've probably also noticed that the altar cloth is purple, and if your church normally has flowers or plants near the altar, those have been removed. You may also have noticed that the Gloria ("Glory to God in the highest") is not sung during Advent, either.
All of these things are signs of the penitential nature of Advent and a reminder that the Christmas season hasn't started yet. I've mentioned before that Advent was once known as a "little Lent," and so the penitential color of purple makes an appearance, the organ is muted, and the Gloria--one of the most festive hymns of the Mass--isn't sung. Our thoughts, even on Sunday, are supposed to be on preparing ourselves for the coming of Christ, both at Christmas and at the Second Coming.
Just as during Lent, however, the Church allows us some rest as we pass the halfway point of Advent. The third Sunday of Advent is known as Gaudete Sunday, because "Gaudete" ("Rejoice") is the first word of the entrance antiphon at that Mass. On that Sunday, your priest will likely wear rose vestments--a color that still reminds us of the penitential purple, but also has a lightness and joy to it, reminding us that Christmas is drawing near.