"Luther's insight was shockingly simple, as great ideas always are: God does not need your good works, but your neighbor does. That realization opened for Luther a new relationship that refused to make either creation or the law the means of salvation but to use them for helping others in need. God intends to manufacture good works through you for others, by hook or by crook, because there are real people and things in the world that need your help."
Peter takes a while to get going -- he does a little stand-up comedy at the beginning but once he gets to the point, it's great stuff. If you're not into comedy, you have time to grab a cup of coffee before he gets there (starting at about 4:15 or so). On the other hand, you might enjoy his particular brand of humor. You may have to right click (or ctrl-click for Mac) and turn HD off if you have trouble playing the video.
Either way, we're called to make a difference in the world. Big or small, the lives of Christ-followers should do violence to the world's systems of injustice. You can do good stuff in tiny ways -- paying for the person behind you in the drive-thru at Burger King, maybe, or mowing your neighbor's yard -- or in big ways, caring for dying lepers in the streets of Calcutta like Mother Teresa. But in the end, it's the same thing.
It's what Jesus called "the kingdom of God." It breaks into the systems and powers of this world and turns them upside-down.