As the saints will rejoice in all goods, so will the damned grieve for all goods.
Man should not consider his material possession his own, but as common to all, so as to share them without hesitation when others are in need.
The theologian considers sin mainly as an offence against God; the moral philosopher as contrary to reasonableness.
Perfection of moral virtue does not wholly take away the passions, but regulates them.
As regards the individual nature, woman is defective and misbegotten, for the active power of the male seed tends to the production of a perfect likeness in the masculine sex; while the production of a woman comes from defect in the active power.
Justice is a certain rectitude of mind whereby a man does what he ought to do in the circumstances confronting him.
Distinctions drawn by the mind are not necessarily equivalent to distinctions in reality.
It is possible to demonstrate God's existence, although not a priori, yet a posteriori from some work of His more surely known to us.
In order for a war to be just, three things are necessary. First, the authority of the sovereign. Secondly, a just cause. Thirdly, a rightful intention.
If forgers and malefactors are put to death by the secular power, there is much more reason for excommunicating and even putting to death one convicted of heresy.
The apostles and their successors are God's vicars in governing the Church which is built on faith and the sacraments of faith. Wherefore, just as they may not institute another Church, so neither may they deliver another faith, nor institute other sacraments.
The principal act of courage is to endure and withstand dangers doggedly rather than to attack them.
The knowledge of God is the cause of things. For the knowledge of God is to all creatures what the knowledge of the artificer is to things made by his art.
Because of the diverse conditions of humans, it happens that some acts are virtuous to some people, as appropriate and suitable to them, while the same acts are immoral for others, as inappropriate to them.
To live well is to work well, to show a good activity.
Temperance is simply a disposition of the mind which binds the passion.
Hold firmly that our faith is identical with that of the ancients. Deny this, and you dissolve the unity of the Church.
How is it they live in such harmony the billions of stars - when most men can barely go a minute without declaring war in their minds about someone they know.
Every judgement of conscience, be it right or wrong, be it about things evil in themselves or morally indifferent, is obligatory, in such wise that he who acts against his conscience always sins.
To one who has faith, no explanation is necessary. To one without faith, no explanation is possible.
Better to illuminate than merely to shine, to deliver to others contemplated truths than merely to contemplate.
Clearly the person who accepts the Church as an infallible guide will believe whatever the Church teaches.
A man has free choice to the extent that he is rational.
Fear is such a powerful emotion for humans that when we allow it to take us over, it drives compassion right out of our hearts.
If, then, you are looking for the way by which you should go, take Christ, because He Himself is the way.
It is requisite for the relaxation of the mind that we make use, from time to time, of playful deeds and jokes.
If the highest aim of a captain were to preserve his ship, he would keep it in port forever.