"The first half is, 'Work out your own salvation with fear and trembling'--which looks as if everything depended on us and our good actions: but the second half goes on, 'For it is God who worketh in you'"

Philippians 2:12-13 (KJV): "Wherefore, my beloved, as ye have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling. For it is God which worketh in you both to will and to do of his good pleasure."