Derek Brown is owner and operator of Brownsford Window Cleaning Company, LLC, and is currently working on a M.Div. at The Southern Baptist Theological Seminary. He is a good friend of mine, and a faithful brother. He recently wrote an excellent piece regarding responsibilities and productivity for the glory of God. A book written by John Piper stimulated his clearly articulated and deeply convicting reflections. For your benefit, I highly recommend you read his thoughts. They can be found here.