"The reason for the predestination of some, and reprobation of others..."

Image: Thomas Aquinas

The reason for the predestination of some, and reprobation of others, must be sought for in the goodness of God. Thus He is said to have made all things through His goodness, so that the divine goodness might be represented in things. Now it is necessary that God's goodness, which in itself is one and undivided, should be manifested in many ways in His creation; because creatures in themselves cannot attain to the simplicity of God. Thus it is that for the completion of the universe there are required different grades of being; some of which hold a high and some a low place in the universe. That this multiformity of grades may be preserved in things, God allows some evils, lest many good things should never happen, as was said above (I:22:2). Let us then consider the whole of the human race, as we consider the whole universe. God wills to manifest His goodness in men; in respect to those whom He predestines, by means of His mercy, as sparing them; and in respect of others, whom he reprobates, by means of His justice, in punishing them. This is the reason why God elects some and rejects others. To this the Apostle refers, saying (Romans 9:22-23): "What if God, willing to show His wrath [that is, the vengeance of His justice], and to make His power known, endured [that is, permitted] with much patience vessels of wrath, fitted for destruction; that He might show the riches of His glory on the vessels of mercy, which He hath prepared unto glory" and (2 Timothy 2:20): "But in a great house there are not only vessels of gold and silver; but also of wood and of earth; and some, indeed, unto honor, but some unto dishonor." Yet why He chooses some for glory, and reprobates others, has no reason, except the divine will. Whence Augustine says (Tract. xxvi. in Joan.): "Why He draws one, and another He draws not, seek not to judge, if thou dost not wish to err." Thus too, in the things of nature, a reason can be assigned, since primary matter is altogether uniform, why one part of it was fashioned by God from the beginning under the form of fire, another under the form of earth, that there might be a diversity of species in things of nature. Yet why this particular part of matter is under this particular form, and that under another, depends upon the simple will of God; as from the simple will of the artificer it depends that this stone is in part of the wall, and that in another; although the plan requires that some stones should be in this place, and some in that place. Neither on this account can there be said to be injustice in God, if He prepares unequal lots for not unequal things. This would be altogether contrary to the notion of justice, if the effect of predestination were granted as a debt, and not gratuitously. In things which are given gratuitously, a person can give more or less, just as he pleases (provided he deprives nobody of his due), without any infringement of justice. This is what the master of the house said: "Take what is thine, and go thy way. Is it not lawful for me to do what I will?" (Matthew 20:14-15).

Thomas Aquinas, Summa Theologica (Part 1, Question 23, Article 5, Reply to Objection 3)