Pastor John Piper warns of attempting to "do great things for God":

The difference between Uncle Sam and Jesus Christ is that Uncle Sam won't enlist you unless you are healthy and Jesus won't enlist you unless you are sick. What is God looking for in the world? Assistants? No. The gospel is not a help wanted ad. It is a help available ad. God is not looking for people to work for him but people who let him work mightily in and through them.