Philippians 2:12-13 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, for it is God who works in you, both to will and to work for his good pleasure.
Though we can’t earn salvation through good works, not all of the effects of salvation can be seen immediately in us and we’re called to persevere in our faith and “work out” our salvation. As we progress in our walk with Christ, God works in and through us.
At the point we would call conversion, we do become new creations (2 Corinthians 5:17), our old nature dying and our new nature being in Christ. It’s through persevering faith, though, that we really take on the new attributes of a Christ-follower, the fruits. The Holy Spirit works in us “to will and to work for His good pleasure”. This means our very desires begin to change because of God’s work in us. We don’t just change because we think we’re supposed to change, we change because we now desire to do so. Our wants begin to align with God’s will and purpose.
When we follow Christ, we take on His plans as our own and God has us bring about His will by transforming us to be more like Him.