In answering the question posed in Romans 9:14, namely whether there is any injustice with God, the apostle Paul immediately appeals to the inspired Scriptures, specifically the words of the Lord to Moses concerning his Name in Exodus 33:19: For he says to Moses, I will have mercy on whom I have mercy, and I will have compassion on whom I have compassion
(Romans 9:15). Twice the Lord repeats the positives of mercy and compassion. This highlights that God wants to do what is best for people, and he himself determines how to distribute his favour. One cannot simply turn these words around as if the reverse would be I will be unmerciful to whom I want to be unmerciful, and I will hate those whom I want to hate.
The reverse is something else, namely that it is not the accomplishments of people that merits God’s mercy and his compassion, but that his distribution thereof is wholly dependent upon his own sovereign decree. For this reason Paul continues by noting that it depends not on human will or exertion, but on God, who has mercy
(Romans 9:16). This statement complements the examples given earlier, for Isaac had not yet even been conceived when God had already reserved a special position for him, and Jacob was still in his mother’s womb, together with his twin brother, Esau, when God appointed him to a position of precedence. This teaches us that God’s compassion over someone has nothing to do with the will or desires of that man himself nor with how his life turns out. Before a child’s conception and birth, the child has no will and has not yet made any decisions. The implicit message for the readers here in Romans 9:15–16 is that their calling as Gentile Christians has nothing to do with their own virtue or merit.1
15 For he says to Moses, “I will have mercy on whom I have mercy, and I will have compassion on whom I have compassion.”