Churches that use the Revised Common Lectionary find some of their scripture texts and sermons are about repentance and Christ's second coming of judgment. It's possible, of course, to skirt these texts and choose only the ones that are about hope, joy, and the coming of a better world through the Messiah. But even these texts hold an aspect of repentance in them. The hope of a better world is one where the rough places will be made straight, the poor will be fed, injustice will be no more, safety and peace will reign.
Excuse me, but those things will not happen unless humans wake up and start living in different ways. In other words, we need to be about repentance. The Messiah comes, in part, to provide a example to us about what living out God's priorities looks like. He comes in part to enable us to do it ourselves. And he comes, in part, to provide forgiveness for those who realize they have not been living as God desires. Those who repent.
"Repent, for the Kingdom of Heaven has come near!" -- John, Matthew 3:2It's no accident that both John the Baptist and Jesus make repentance—turning away from the way you used to live, and living a new way in accordance with God's commands—the focus of their preaching. God's message to us has been all about repentance ever since we first started sinning. What is the message of the Old Testament prophets? Repentance. What do Jesus and John the Baptist and Paul and others in the New Testament emphasize? Repentance.
"Repent, for the Kingdom of Heaven has come near!" -- Jesus, Matthew 4:17
So in Advent it should come as no surprise as we prepare for Christ's coming and the promise it holds for the world, that part of our preparation is to repent. In the clutter of the "Shopmas" season, taking the time to take stock and repent is one of the best ways we can honor the birth of our Lord.