Let me make what I have been saying personal. Are you a believer in Jesus Christ? Are you trusting Him for your salvation? Has the Holy Spirit made you alive in Jesus Christ? If he has, what can be more reasonable than to give yourself to Him? What is more logical than to serve God wholeheartedly in this way?
It is also reasonable because of what God is continuing to do. The salvation of a Christian is not just a past thing. It is also a present experience, because God is continuing to work in those whom He has brought to faith in Jesus Christ. It is difficult to make changes in our lives, break destructive habits, form new ways of thinking and please God. But this is exactly what God is doing in us. It is what this text is about. God does not start a thing and abandon it. When God starts something He always brings it to completion. He is doing this with you. Therefore, it is absurd to oppose His purposes. It is futile. The only reasonable thing is to join God and get on with what He is leading you to do.
It is also reasonable to serve God sacrificially because such service is God’s will for us, and His is a good, pleasing and perfect will. Christians often get greatly hung up on the idea of discovering “what God’s specific will is” for their lives. In my judgment, there clearly are specific plans for our lives that God has determined in advance, because He has predetermined all things. The difficulty is that He has not revealed these to us. But although these specific details are not made known, general but very important things are, and the most important of these general things is that God wants us to be like Jesus Christ.
Sometimes we also get hung up on the idea that God’s will must be something hard, difficult or irrational. Paul corrects that error by giving us three adjectives to describe the nature of God’s will.
It is “good,” he says. God is the master of the understatement. So if God says His will is good, He means good with a capital “G.” He means that His will for us is the best thing that could possibly be.
God’s will is also “acceptable,” says Paul. This means acceptable to us, since the fact that God’s will is acceptable to God goes without saying. Do not say that the will of God is hard or difficult or irrational. If you are thinking along those lines, it is because you have not yet learned to surrender to it. Those who do surrender to God’s will, offering their whole selves as sacrifices to Him, find that the will of God is the most acceptable thing there can be.
Finally, Paul argues that the will of God is “perfect.” No one can say more than that. Our ways are not perfect. They can always be improved upon and often must be corrected. God’s ways are perfect. They can never be improved upon. So isn’t it the most reasonable thing in the world to serve God and to do so without reservation, with all your heart?