Charles Ellicott Commentary Romans 9:16

"So then it is not of him that willeth, nor of him that runneth, but of God that hath mercy." — Romans 9:16 (ASV)

Of him that runneth.—A metaphor taken from the foot-races as St. Paul may very possibly have seen them practised at Corinth. (Galatians 2:2; Galatians 5:7; Philippians 2:16.) The meaning is that the prize does not depend on human will or human effort, but on the grace of God.