Quote from here: http://www.desiringgod.org/articles/god-s-big-work-and-our-little-mission

We don’t do what we do out of our need to become. We do what we do because in Christ we already are. We are a new creation created in Jesus Christ for good works that he prepared in advance for us to do (Ephesians 2:10). Our “being in Christ” leads to our “Christ-like doing.”

We do what we do because of what we believe he has done.

We love because we are loved by him first.

We serve because we were served by Jesus first.

 http://www.desiringgod.org/articles/god-s-big-work-and-our-little-mission