Aquinas on Rom 9

Some excerpts from the Angelic Doctor's commentary on Rom 9:

*************************************************************

First, the greatness of the benefit conferred on us by the Holy Spirit, namely, that all things work together for good.

To realize this we should consider that whatever happens in the world, even if it be evil, accrues to the good of the universe; because, as Augustine says in Enchiridion: “God is so good that he would permit no evil, unless he were powerful enough to draw some good out of any evil.”

However, the evil does not always accrue to the good of that in which it is. Thus, the death of one animal accrues to the good of the universe, inasmuch as by the destruction of one thing something else begins to be, although it does not accrue to the good of that which ceases to be; because the good of the universe is willed by God according to itself and to this good all the parts of the universe are ordained (341).

For it is clear that distributive justice has its field in things given as due; for example, if some persons have earned wage, more should be given to those who have done more work. But it has no place in things given spontaneously and out of mercy; for example, if a person meets two beggars and gives one an alms, he is not unjust but merciful. Similarly, if a person has been offended equally by two people and he forgives one but not the other, he is merciful to the one, just to the other, but unjust to neither.

For since all men are born subject to damnation on account of the sin of the first parent, those whom God delivers by His grace He delivers by His mercy alone; and so He is merciful to those whom He delivers, just to those whom He does not deliver, but unjust to none (382).

To understand his answer it should be noted that with regard to the election of the good and the rejection of the wicked two questions can arise. One is general, namely, why does God will to harden some and be merciful to some; the other is particular, namely, why does He will to be merciful to this one and harden this or that one?

Although a reason other God's will can be assigned, in the first question the only reason that can be assigned in the second question is God's absolute will. An example is found among humans. For if a builder has at hand many similar and equal stones, the reason why he puts certain ones at the top an others at the bottom can be gathered from his purpose, because the perfection of the house he intends to build requires both a foundation with stones at the bottom and walls of a certain height with stones at the top. But the reason why he put these stones on the to and those others at the bottom seems to be merely that the builder so willed.

First, therefore, the Apostle answers the problem involved in the second question, namely why He has mercy on this one and hardens that one; secondly, the problem involved in the first question, namely, why He is merciful to some and hardens others (390-91).

Then (v. 22) he answers the first question, namely, why God wills to be merciful to some and leave others in wretchedness, i.e., to choose some and reject others. Here it should be noted that the end of all divine works ins the manifestation of divine goodness: "The Lord has made all things for himself" (Pr 16:4). Hence, it was stated above that the invisible things of God have been clearly perceived in the things that have been made (1:20).

But the excellence of the divine goodness is so great that it cannot be manifested in one way or in one creature. Consequently, he created diverse creatures in which He is manifested in diverse ways. This is particularly true in rational creatures in whom is justice is manifested with regard to those he benefits according to their deserts and His mercy in those He delivers by His grace. Therefore, to manifest both of these in man He mercifully delivers some, but not all (393).

http://www.aquinas.avemaria.edu/Aquinas_on_Romans.pdf