Romans 9:18

(15) Therefore hath he mercy on whom he (t) will [have mercy], and whom he will he hardeneth.

(15) A conclusion of the full answer to the first objection: therefore seeing that God does not save those whom he freely chose according to his good will and pleasure, but by justifying and sanctifying them by his grace, his counsels in saving them cannot seem unjust. And again, there is not injustice in the everlasting counsel of God, with regard to the destruction of those whom he lifts to destroy, because he hardens before he destroys: therefore the third answer for the maintenance of God's justice in the everlasting counsel of reprobation, consists in this word "hardening": which nonetheless he concealed in the former verse, because the history of Pharaoh was well known. But the force of the word is great, for hardening, which is set against "mercy", presupposes the same things that mercy did, that is, a voluntary corruption, in which the reprobate are hardened: and again, corruption presupposes a perfect state of creation. Moreover, this hardening also is voluntary, for God hardens in such a way, being offended with corruption, that he uses their own will whom he hardens, for the executing of that judgment. Then follow the fruits of hardening, that is, unbelief and sin, which are the true and proper causes of the condemnation of the reprobate. Why does he then appoint to destruction? Because he wishes: why does he harden? Because they are corrupt: why does he condemn? Because they are sinners. Where then is unrighteousness? Nay, if he would destroy all after this manner, to whom would he do injury?

(t) Whom it pleased him to appoint, to show his favour upon.