It may well happen that what is in itself the more certain on account of the weakness of our intelligence, which is dazzled by the clearest objects of nature; as the owl is dazzled by the light of the sun. Hence the fact that some happen to doubt about articles of faith is not due to the uncertain nature of the truths, but to the weakness of human intelligence; yet the slenderest knowledge that may be obtained of the highest things is more desirable than the most certain knowledge obtained of lesser things...
The fact that the evil ones, as long as they live, can be corrected from their errors does not prohibit that they may be justly executed, for the danger which threatens from their way of life is greater and more certain than the good which may be expected from their improvement.
The magnitude of the punishment matches the magnitude of the sin. Now a sin that is against God is infinite; the higher the person against whom it is committed, the graver the sin-it is more criminal to strike a head of state than a private citizen-and God is of infinite greatness. Therefore an infinite punishment is deserved for a sin committed against Him.
[It is appropriate that the Body and Blood of Christ be truly present in this Sacrament] because of the perfection of the New Covenant. The sacrifices of the Old Covenant contained the true sacrifice of Christ's Passion only in symbol....Therefore it was necessary that the sacrifice of the New Covenant, instituted by Christ, have something more, namely, that it contain Christ Himself who has suffered and contain Him not only in symbol but in reality.
Give us, O Lord, a steadfast heart, which no unworthy affection may drag downwards; give us an unconquered heart, which no tribulation can wear out; give us an upright heart, which no unworthy purpose may tempt aside. Bestow upon us also, O Lord our God, understanding to know you, diligence to seek you, wisdom to find you, and a faithfulness that may finally embrace you; through Jesus Christ our Lord.
Given the sin of impiety through which they [the Romans] sinned against the divine nature [by idolatry], the punishment that led them to sin against their own nature followed.... I say, therefore, that since they changed into lies [by idolatry] the truth about God, He brought them to ignominious passions, that is, to sins against nature; not that God led them to evil, but only that he abandoned them to evil....
Charity is not a potency of the soul, because if it were it would be natural. Nor is it a passion, because it is not in a sensitive potency in which are all passions. Nor is it a habit, because a habit is removed with difficulty; charity, however, is easily lost through one act of mortal sin. Therefore charity is not something created in the soul.
Secondly, man sins against nature when he goes against his generic nature, that is to say, his animal nature. Now, it is evident that, in accord with natural order, the union of the sexes among animals is ordered towards conception. From this it follows that every sexual intercourse that cannot lead to conception is opposed to man's animal nature.
In questions of this sort there are two things to be observed. First, that the truth of the Scriptures be inviolably maintained. Secondly, since Scripture doth admit of diverse interpretations, that no one cling to any particular exposition with such pertinacity that, if what he supposed to be the teaching of Scripture should afterward turn out to be clearly false, he should nevertheless still presume to put it forward, lest thereby the sacred Scriptures should be exposed to the derision of unbelievers and the way of salvation should be closed to them.
Even as in the blessed in heaven there will be most perfect charity, so in the damned there will be the most perfect hate. Wherefore as the saints will rejoice in all goods, so will the damned grieve for all goods. Consequently the sight of the happiness of the saints will give them very great pain.
Natural inclinations are present in things from God, who moves all things. So it is impossible for the natural inclinations of a species to be toward evil in itself. But there is in all perfect animals a natural inclination toward carnal union. Therefore it is impossible for carnal union to be evil in itself.
Just as a man cannot live in the flesh unless he is born in the flesh, even so a man cannot have the spiritual life of grace unless he is born again spiritually. This regeneration is effected by Baptism: "Unless a man is born again of water and the Holy Spirit, he cannot enter into the kingdom of God" (Jn 3:5)
It is on account neither of God's weakness nor ignorance that evil comes into the world, but rather it is due to the order of his wisdom and the greatness of his goodness that diverse grades of goodness occur in things, many of which would be lacking if no evil were permitted. Indeed, the good of patience would not exist without the evil of persecution; nor the good of preservation of life in a lion if not for the evil of the destruction of the animals on which it lives.
If you seek patience, you will find no better example than the cross. Great patience occurs in two ways: either when one patiently suffers much, or when one suffers things which one is able to avoid and yet does not avoid. Christ endured much on the cross, and did so patiently, because when he suffered he did not threaten; he was led like a sheep to the slaughter and he did not open his mouth.
Without the suitable conditions life could not exist. But both life and its conditions set forth the operations of inscrutable Power. We know not its origin; we know not its end. And the presumption, if not the degradation, rests with those who place upon the throne of the universe a magnified image of themselves, and make its doings a mere colossal imitation of their own. Wonder was the motive that led people to philosophy ... wonder is a kind of desire in knowledge. It is the cause of delight because it carries with it the hope of discovery.
He (Mohammed) seduced the people by promises of carnal pleasure to which the concupiscence of the flesh urges us. His teaching also contained precepts that were in conformity with his promises, and he gave free rein to carnal pleasure. In all this, as is not unexpected; he was obeyed by carnal men. As for proofs of the truth of his doctrine, he brought forward only such as could be grasped by the natural ability of anyone with a very modest wisdom. Indeed, the truths that he taught he mingled with many fables and with doctrines of the greatest falsity.