Romans 9:15

(11) For he saith to Moses, I will (o) have mercy on whom I will have mercy, and I will have (p) compassion on whom I will have compassion.

(11) He answers first with regard to those who are chosen to salvation, in the choosing of whom he denies that God may seem unjust, although he chooses and predestinates to salvation those that are not yet born, without any respect of worthiness: because he does not bring the chosen to the appointed end except by the means of his mercy, which is a cause discussed under predestination. Now mercy presupposes misery, and again, misery presupposes sin or voluntary corruption of mankind, and corruption presupposes a pure and perfect creation. Moreover, mercy is shown by her degrees: that is, by calling, by faith, by justification and sanctification, so that at length we come to glorification, as the apostle will show afterwards. Now all these things orderly following the purpose of God, do clearly prove that he can by no means seem unjust in loving and saving his.

(o) I will be merciful and favourable to whom I wish to be favourable.

(p) I will have compassion on whoever I wish to have compassion.