Purpose: To show the evidences of serving God.
Aim: I want the listener to pursue serving God in order to glorify God.
INTRODUCTION: It is easy to SAY we are serving God when we really aren’t. But, it is also possible to put a lot of effort into doing a lot of good religious things and still not be serving God. Jesus gave us an example of this in Matthew 7:22–23 “Many will say to Me on that day, ‘Lord, Lord, did we not prophesy in Your name, and in Your name cast out demons, and in Your name perform many miracles?’ And then I will declare to them, ‘I never knew you; DEPART FROM ME, YOU WHO PRACTICE LAWLESSNESS.’ (NAS) So, God does not always consider good religious works to be done for Him.
How can we know if we are really working for God? We could be doing things that God really doesn’t want us to do, or we could be doing the right things with a wrong motive. How tragic it would be to spend a lot of effort serving God and still not be pleasing to God.
Paul shows us in today’s text how we can be 100% certain that what we are doing for God REALLY is for God.
Vs.4-6a I. We are Serving God if we are Depending on God’s Strength
We can do nothing for God without God’s help. We are saved by grace, but we must also live every moment depending on God’s grace in order to please Him.
“The higher a man is in grace. The lower he will be in his own esteem.” --C.H. Spurgeon
“The ultimate test of our spirituality is the measure of our amazement at the grace of God.” --D. Martyn Lloyd-Jones 
Vs.6b-16 II. We are Serving God if Changed Lives are the Goal
Notice verses 6 & 11. Our passion must be to see God work and change lives. We can be better at organizing; we can have better music, we can have many more outreaches to the community, but if God is not changing sinners into Christians then we are not doing “that which remains is in glory” (Vs.11).
Serving God CANNOT be just something we DO at just certain times. Serving God should be our passion for every waking moment of our lives. “The man who has nothing more than a kind of Sunday religion -- who’s Christianity is like his Sunday clothes put on once a week, and then laid aside -- such a man cannot, of course, be expected to care about growth in grace.” --J.C. Ryle
Vs.17-18 III. We are Serving God if we are Becoming more like Christ
If “the Spirit of the Lord” is present and working then we “are being transformed.”
How often do others comment that they see Christ in you? Do you sense a growing awareness of the awesome glory of God?
“The way to open our hearts to others is by receiving afresh the grace of God and appreciating what it means: seeing our own need of Christ; coming to receive His mercy; sensing how undeserved His love for us is; remembering how He has also opened His heart to those whose hearts are closed against us.” --Sinclair B. Ferguson 
Vs.1-3 IV. We are Serving God if Others are Becoming more like Christ
Paul didn’t care if he had the “right” credentials or not. He said that the fact that lives were becoming more like Christ was all the proof he needed that he was really serving God.
Changed lives were the proof that Paul was obeying the Great Commission. Matthew 28:19–20 “Go therefore and make disciples of all the nations, baptizing them in the name of the Father and the Son and the Holy Spirit, teaching them to observe all that I commanded you; and lo, I am with you always, even to the end of the age.” (NAS)
CONCLUSION: “There is a story that when the famous English architect, Sir Christopher Wren, was directing the building of St. Paul’s Cathedral in London, some of the workers were interviewed by a journalist who asked them, “What are you doing here?”
The first said, “I’m cutting stone for three shillings a day.”
The second replied, “I’m putting ten hours a day in on this job.”
The third replied, “I’m helping Sir Christopher Wren build the greatest cathedral in Great Britain for the glory of God.” 
We have something much more important to do than build a cathedral. God wants to use us to build His church.
Quoted in: Reformation and Revival Journal, v. 13, n. 3, p. 173.
Grow in Grace, Banner of Truth, Carlisle, PA. 1989, p. 88-89.
Robert J. Morgan, Nelson's Complete Book of Stories, Illustrations, and Quotes, electronic ed., 800 (Nashville: Thomas Nelson Publishers, 2000).