"Those who deny Purgatory speak against the justice of God"

"FROM the conclusions we have drawn above (III, 86, 4-5; Suppl., 12, 1) it is sufficiently clear that there is a Purgatory after this life. For if the debt of punishment is not paid in full after the stain of sin has been washed away by contrition, nor again are venial sins always removed when mortal sins are remitted, and if justice demands that sin be set in order by due punishment, it follows that one who after contrition for his fault and after being absolved, dies before making due satisfaction, is punished after this life. Wherefore those who deny Purgatory speak against the justice of God: for which reason such a statement is erroneous and contrary to faith. Hence Gregory of Nyssa, after the words quoted above, adds: "This we preach, holding to the teaching of truth, and this is our belief; this the universal Church holds, by praying for the dead that they may be loosed from sins." This cannot be understood except as referring to Purgatory: and whosoever resists the authority of the Church, incurs the note of heresy."

~St. Thomas Aquinas: Summa theologiae, Suppl. IIIae, Append. 2, A. 1.

Virgin and Child with Souls in Purgatory, by Luca Giordano.

Oil on canvas, c. 1650; San Pietro di Castello, Venice.

"Man should be directed to his end by a law given by God"

"BESIDES the natural and the human law it was necessary for the directing of human conduct to have a Divine law. And this for four reasons. First, because it is by law that man is directed how to perform his proper acts in view of his last end. And indeed if man were ordained to no other end than that which is proportionate to his natural faculty, there would be no need for man to have any further direction of the part of his reason, besides the natural law and human law which is derived from it. But since man is ordained to an end of eternal happiness which is inproportionate to man's natural faculty, as stated above (Q. 5, A. 5), therefore it was necessary that, besides the natural and the human law, man should be directed to his end by a law given by God."

~St. Thomas Aquinas: Summa theologiae, I-II, Q. 91, A. 4.

"Christ dwells in us"

"CHRIST dwells in us, namely, when we know that we hold the faith which the Catholic Church teaches and holds. But if it is taken in regard to the affectivity, then Christ dwells in us by formed faith; and in this way no one can know that Christ dwells in him, or that he has charity, unless this certainty be granted to a person by revelation and a special grace. But there is nothing to prevent us from having a conjecture [coniecturum] that we are in charity, namely, when a person finds himself so ready and disposed that he would not wish to do anything against Christ in any way for something temporal: “Beloved, if our hearts do not condemn us, we have confidence before God” (1 Jn. 3:21)."

~St. Thomas Aquinas: Commentary on 2 Corinthians, (2 Cor. 13:5-10) 13, lect. 2, 527. 

The Temptation of St. Thomas Aquinas, by Bernardo Daddi.

Poplar, 1338; Staatliche Museen, Berlin.

Maritain: "A living Christianity"

“A LIVING Christianity is necessary to the world. Faith must be actual, practical, existential faith. To believe in God must mean to live in such a manner that life could not possibly be lived if God did not exist. For the practical believer, gospel justice, gospel attentiveness to everything human must inspire not only the deeds of the saints, but the structure and institutions of common life, and must penetrate to the depths of terrestrial experience.”

~Jacques Maritain: The Range of Reason.

St. Thomas on Nature and Grace

"RATIONAL natures are poised between alternatives. God moves the human spirit to good; nevertheless it could resist. It is God's doing, then that a man prepares himself to receive grace. If he lacks grace, then the cause of the failure lies in him, not in God."
—Quodlibets, I, 4, 2.

"HENCE man, by his natural endowments, cannot produce meritorious works proportionate to everlasting life; and for this a higher force is needed, viz. the force of grace. And thus without grace man cannot merit everlasting life; yet he can perform works conducing to a good which is natural to man, as to toil in the fields, to drink, to eat, or to have friends, and the like."
—Summa Theologica, I-II, Q. 109, A. 5.

"MAN'S nature may be looked at in two ways: first, in its integrity, as it was in our first parent before sin; secondly, as it is corrupted in us after the sin of our first parent. Now in both states human nature needs the help of God as First Mover, to do or wish any good whatsoever, as stated above (A. 1). But in the state of integrity, as regards the sufficiency of the operative power, man by his natural endowments could wish and do the good proportionate to his nature, such as the good of acquired virtue; but not surpassing good, as the good of infused virtue. But in the state of corrupt nature, man falls short of what he could do by his nature, so that he is unable to fulfil it by his own natural powers. Yet because human nature is not altogether corrupted by sin, so as to be shorn of every natural good, even in the state of corrupted nature it can, by virtue of its natural endowments, work some particular good, as to build dwellings, plant vineyards, and the like; yet it cannot do all the good natural to it, so as to fall short in nothing; just as a sick man can of himself make some movements, yet he cannot be perfectly moved with the movements of one in health, unless by the help of medicine he be cured.

"And thus in the state of perfect nature man needs a gratuitous strength superadded to natural strength for one reason, viz. in order to do and wish supernatural good; but for two reasons, in the state of corrupt nature, viz. in order to be healed, and furthermore in order to carry out works of supernatural virtue, which are meritorious. Beyond this, in both states man needs the Divine help, that he may be moved to act well."
—Summa Theologica, I-II, Q. 109, a. 2.

“SINCE the aptness for grace is part of human nature’s good estate, we can now appreciate how sin diminishes nature. And because grace perfects nature, heightening mind and will and the sensitive parts which serve reason, we can appreciate also how sin, by depriving us of grace and clogging our natural abilities, also hurts nature. The results of sin are ignorance, malice, and concupiscence, and these are called the wounds of nature.”
—Disputations concerning Evil, 11, 11.

"THE justification of the ungodly is brought about by God moving man to justice. For He it is "that justifieth the ungodly" according to Romans 4:5. Now God moves everything in its own manner. . . . It is man's proper nature to have free-will. Hence in him who has the use of reason, God's motion to justice does not take place without a movement of the free-will; but He so infuses the gift of justifying grace that at the same time He moves the free-will to accept the gift of grace, in such as are capable of being moved thus."
—Summa Theologica, I-II, Q. 113, A. 3.

St. Thomas Aquinas, by Fra Angelico.
Tempera on wood, 1340-45; Collezione Vittorio Cini, Venice.