Work It Out!

Phil 2:12-13

12 So then, my beloved, just as you have always obeyed, not as in my presence only, but now much more in my absence, work out your salvation with fear and trembling; 13 for it is God who is at work in you, both to will and to work for His good pleasure.
NASU

Action: Who is responsible for my salvation? Is God working in me?