“So then it is not of him that willeth, nor of him that runneth, but of God that sheweth mercy.”
King James Version (KJV)
9:16 It - The blessing. Therefore is not of him that willeth, nor of him that runneth - It is not the effect either of the will or the works of man, but of the grace and power of God. The will of man is here opposed to the grace of God, and man's running, to the divine operation. And this general declaration respects not only Isaac and Jacob, and the Israelites in the time of Moses, but likewise all the spiritual children of Abraham, even to the end of the world.
Ro 9:16 But of God that sheweth mercy. When God is gracious, it is not because a human will ("him that willeth"), or a human work ("him that runneth") lays him under obligation, and forces him to give, but the gift is of him, due to his mercy, which he has the right to bestow where he will. Isaac "willed" to bestow the blessing on Esau (Ge 27:1-4), and the latter "run" to obtain the venison (Ge 27:5), but Jacob had been chosen to become the founder of the chosen people (Ge 25:23 26:24 Ps 135:4), and received the blessing, which promised that he should be the father of a great nation (Ge 27:28,29).