John Calvin Commentary 1 Corinthians 9:26

"I therefore so run, as not uncertainly; so fight I, as not beating the air:" — 1 Corinthians 9:26 (ASV)

I therefore so run. He returns to speak of himself, so that his doctrine may have more weight, by presenting himself as an example. What he says here some refer to assurance of hope (Hebrews 6:11)— “I do not run in vain, nor do I run the risk of losing my labor, for I have the Lord’s promise, which never deceives.” It rather appears to me, however, that his object is to direct the course of believers straight forward toward the goal, so that it is not wavering and devious.

“The Lord exercises us here in the way of running and wrestling, but He sets before us the object at which we should aim, and prescribes a sure rule for our wrestling, so that we do not weary ourselves in vain.” Now he includes both the comparisons that he had employed.

“I know,” he says, “where I am running, and, like a skillful wrestler, I am anxious that I do not miss my aim.” These things should ignite and strengthen the Christian heart, so that it devotes itself with greater alacrity to all the duties of piety; for it is very important not to wander in ignorance through uncertain paths.