So then it is not of him that wills, nor of him that runs, but of God that shows mercy.
All Commentaries on Romans 9:16 Go To Romans 9
Jerome
AD 420
It is clear from this passage that the willing and running are ours, but the fulfillment of our willing and running belongs to the mercy of God. So it is that free will is preserved as far as our willing and running is concerned and that everything depends on the power of God as far as the fulfillment of our willing and running is concerned.