The word that is used for salvation is also used in verses 1:19 and 1:28; both of these verses indicate salvation from an event or situation. This view is highlighted by the use of the word fear, which actually implies a fear of wrath, but I assume is used to convey a sense of reverance for God.
On the other side, salvation is spoken about as if it is a process, but not one by which we gain justification, that would be contradictory to the Christian view of salvation. Paul might have been speaking of salvation in a sanctifying sense. This also could be related to the use of the word salvation in verse 1:19 where Paul says that he believes he will be "delivered." Salvation in this sense might mean being saved from our current situation; it might mean being saved from our sins themselves, and not just their consequences, immediate and future.
Wesley looked at this verse from a different view, believing instead that Paul was encouraging the Philippians to "secure the salvation which Christ had purchased." This view helps to better incorporate both views, though I would have worded it differently. I would have emphasised the importance of continuing in the salvation we have already recived so that we can be saved on the Day of Christ, rather than the idea of securing that salvation.
Verse 13- .
This verse clarifies the use of fear in verse 12. We should work out our salvation with fear and trembling, why? Because it is God who works in us. This is also one of those places in scripture where the line is blurred between our actions and the actions of God in us. Matthew Henry portays this as an encouragement to the Philippians, God working in us lets us know that our work is not in vain.
Someone could put an emphasis on the fact that Paul places "will" before "act." Though God can strengthen our will through action, we can't act without any will to do so. It seems that Paul might be indicating that Christ is more concerned with changing the inner person prior to desiring that they act differently.
