God has saved us through Jesus Christ, and is now working in us to transform us into the image of Christ. We must respond to his working and fully work out the implications of our salvation.
Lights in the World
12 Therefore, my beloved, as you have always obeyed, so now, not only as in my presence but much more in my absence, work out your own salvation with fear and trembling, 13 for it is God who works in you, both to will and to work for his good pleasure.
Philippians 2:12-13 English Standard Version (ESV)