Like a sailboat equipped with the most sophisticated guidance technology, our Christian lives are often decked out with the latest principles for living, with spiritual guidance counselors telling us what will make life really work for us and our families. Oftentimes, brand new Christians sail out of the harbor under full sail, eager to follow the guidance system, making use of all the gadgets, enthusiastically listening to every fellow boater who has some advice to offer. Yet as many long-time believers know, eventually the winds die down and we find ourselves dead in the water. Then when storm clouds gather on the horizon, we discover that all of the guidance technology and good advice in the world cannot fill our sails so that we can return safely to the harbor. The equipment can plot our course, tell us that a storm is coming, and indicate our present location, but it cannot move us one inch toward the safety of the harbor. In other words, if we are looking for motivation in the Christian life, it cannot come from motivational principles; only the gospel fills our sails…While God’s wise directions are necessary, apart from the ever present word of promise that despite our failures at sea, God is at the helm piloting us to safety, we will eventually give up on sailing altogether. Purposes, laws, principles, suggestions, and good advice can set our course, but only the gospel promise can fill our sails and restore to us the joy of our salvation.
Michael Horton - The Gospel Driven Life, pg. 143-144
(h/t - Tullian Tchividjian)