I therefore so run. — The Apostle appeals to his own conduct as an illustration of the lesson which he is teaching, and by means of it reminds the reader that the whole of this chapter has been a vindication of his own self-denial, and that he has a clear and definite object in view.
So fight I. — The illustration is changed from running to boxing, both being included in the word used in 1 Corinthians 9:25, “contending.” He has an adversary to contend against, and he strikes him, and does not wildly and impotently strike at him, and so only beat the air.