Salvation is something that happens instantly. When we repent of our sins and accept what Jesus did on the cross to pay for those sins we're saved at that point. We're then sealed by the Holy Spirit for the day of redemption.

Paul said that repentance needed to be accompanied by deeds.

(Acts 26:20 NIV) First to those in Damascus, then to those in Jerusalem and in all Judea, and to the Gentiles also, I preached that they should repent and turn to God and prove their repentance by their deeds.

We're saved by faith alone but not by faith that is alone.

You can't "work out" your salvation because it's by grace that we're saved and not by works. One Bible commentary says this about that verse:

In this article I have argued that Phil 2:12 is not dealing with eternal salvation at all. Rather, it is dealing either with temporal salvation from the calamities which come upon the disobedient or with temporal salvation through the trials which faithful believers face.