Thomas Aquinas

Moral science is better occupied when treating of friendship than of justice.

Distinctions drawn by the mind are not necessarily equivalent to distinctions in reality.

Reason in man is rather like God in the world.

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.

Wonder is the desire for knowledge.

Now this relaxation of the mind from work consists on playful words or deeds. Therefore it becomes a wise and virtuous man to have recourse to such things at times.

Whatever is received is received according to the nature of the recipient.

God should not be called an individual substance, since the principal of individuation is matter.

To convert somebody go and take them by the hand and guide them.

The test of the artist does not lie in the will with which he goes to work, but in the excellence of the work he produces.

To live well is to work well, to show a good activity.

Well-ordered self-love is right and natural.

All that is true, by whomsoever it has been said has its origin in the Spirit.

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.

Not everything that is more difficult is more meritorious.

Perfection of moral virtue does not wholly take away the passions, but regulates them.

Hold firmly that our faith is identical with that of the ancients. Deny this, and you dissolve the unity of the Church.

The theologian considers sin mainly as an offence against God; the moral philosopher as contrary to reasonableness.

That the saints may enjoy their beatitude and the grace of God more abundantly they are permitted to see the punishment of the damned in hell.

Three conditions are necessary for Penance: contrition, which is sorrow for sin, together with a purpose of amendment; confession of sins without any omission; and satisfaction by means of good works.