Romans 9:14 - Wesley's Explanatory Notes

Is there injustice with God — Is it unjust in God to give Jacob the blessing rather than Esau? or to accept believers, and them only. God forbid — In no wise. This is well consistent with justice; for he has a right to fix the terms on which he will show mercy, according to his declaration to Moses, petitioning for all the people, after they had committed idolatry with the golden calf. I will have mercy on whom I will have mercy — According to the terms I myself have fixed. And I will have compassion on whom I will have compassion — Namely, on those only who submit to my terms, who accept of it in the way that I have appointed.