This is a pretty intense first reading today. Paul lays out how challenging the Christian life is meant to be. The first line sums up as "well you haven't died yet so keep working." As the athlete disciplines his or her body, so we must discipline ourselves in the habits of discipleship.
Discipline isn't easy. Paul says himself, "all discipline seems a cause not for joy but for pain." But it's through the every day effort and habit-building that "later it brings the peaceful fruit of righteousness to those who are trained by it."
Have you thought of your Christian life as training? Are you working out your discipleship muscles by prayer, fasting, and the sacramental life? Or is your faith just another thing you do? If it doesn't affect every interaction, every decision you make, every moment of your day, I challenge you to have the humility to recognize that you still have a ways to go. I certainly do!