It's the next verse that makes sense out of the Phil 2:12..fear and trembling...you will find when you do a study on "fear and trembling"..it is in response to the goodness of Jesus....like the woman with the issue of blood..she came back to Jesus with fear and trembling..knowing what had happened to her....it's the awe and respect of the goodness of God exhibited in our life..
It is God in us that is at work in us both to will and to do His good pleasure....
Philippians 2:12-13 (NASB)
[SUP]12 [/SUP] 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;
[SUP]13 [/SUP] for it is God who is at work in you, both to will and to work for His good pleasure.