Based on: Philippians 2:12-13 (NIV)

Therefore, my dear friends, as you have always obeyed—not only in my presence, but now much more in my absence—continue to work out your salvation with fear and trembling, for it is God who works in you to will and to act in order to fulfill his good purpose.

Excerpt:

It is this redemptive love of God that Paul says “works in” us to fulfill God’s purpose for our lives. Our efforts toward holy living are strengthened by the love of God. Even when we do not believe that we can be better or do better, God’s love shows that we can.