1 Corinthians 9:26

I therefore so run, not as uncertainly; so fight I, not as one that beateth the air (KJV)

Then: The Corinthians who attended the Isthmian games lived in a time of individual, not team, competitions (Baker, p. 136). Avid fans could pick out which athletes were serious and which ones were just marking time. Paul locks into that knowledge to describe his own work for the Lord. He had his mind made up, knew what he had to do to be successful, and didn't just pretend to follow the Lord with "for-show" motions.

Now: The desire to win is strong in almost every individual. When channeled into the service of the Lord, results can be astounding. That's why many look at the work of Paul and wonder how can it be duplicated in today's world. Paul does not hide his strategy and beliefs. Those who emulate him can be just as fruitful in the Lord's work.

Extra source: Cornerstone Biblical Commentary 1Corinthians (William Baker), 2 Corinthians (Ralph Martin & Carl Toney), ed. by Philip Comfort. Carol Stream: Tyndale House Publishers, c2006.