"The Bible does not say, 'God is at work in you to bring about his good purpose, therefore stay in bed.'  It says, 'Work out your salvation, because God is at work in you'(see Phil. 2:12-13).  God's work does not make our work unnecessary; it makes it possible.  'I work harder than any of them, though it was not I, but the grace of God that is with me'(1 Cor. 15:10)."

(John Piper)