Salvation is through faith from Jesus alone but we work with Him because we have to obey Him when He tells us to do something. So it is synergy right there. Paul tells us to work our salvation out with fear and trembling.
I really expect to be flamed but sorry am not going to change that.
Fear and trembling will definitely be involved in the battle...as the old sin-nature is removed and Holy Spirit moves forward in taking more territory.
We "work out" our salvation in humility and respect (fear and trembling) knowing that God is working through us. Thus when we see someone come to the knowledge of Christ or experience any other good deed through our actions, we need to take pause that it is not we who brought that about but Christ working in us. The honor goes to Him.
And I should also add that perhaps we may not see any works at all in our lives. We can rest assured that as we abide in Christ, He is working through us to create those good works. This is a promise of God. So, once again, we should not be down hearted when we see no works. Instead we should act out of faith with "fear and trembling" through constant and consistent obedience knowing that He is working through us-whether we can see it or not.
What we have to fear is the sinfulness of pride or believing we are useless. What we need to recognize is God's ability to create in us good works-but these good works come from the Son through the Spirit to glorify the Father. They do not come from us.