9:11 purpose of God. God is Creator of all, and needs no human justification for His actions. It is His prerogative to choose whomever He will. We can be confident that His “purpose” is good and holy, whether or not we understand it now; it is our responsibility simply to trust and thank Him.
9:11 not of works. Before Esau and Jacob were born, they had no record of works, so God could not have chosen one of them on that basis. But neither had either one yet exhibited either faith or rebellion, so God’s election of Jacob rather than Esau was not because of either works or faith, “but of Him that calleth.” In due time, of course, Jacob did manifest saving faith and demonstrate its validity by his works, but both had been foreordained by God in ways inscrutable to man.
9:12 serve the younger. This revelation expressing God’s purpose had been given to Rebekah while the twins were struggling in her womb (Genesis 25:22-23), and she undoubtedly transmitted this word to Isaac, but the latter nevertheless continued to favor Esau over Jacob until God overruled him in traumatic fashion (see notes on Genesis 25–27). It is noteworthy that, in the line of the promised seed, God often chose a younger son, over-riding the natural human tendency to choose the elder (e.g., Seth over Cain, Shem over Japheth, Isaac over Ishmael, Judah over Reuben, Pharez over Er, David over Eliab). Of all in the line of promise whose brothers’ names are given, only Abraham and Jesus Himself were firstborn sons.
9:13 it is written. See Malachi 1:2-3. Undoubtedly, “hated” is used here only in a relative sense. Note a similar usage by Jesus (Luke 14:26).