Thomas Aquinas

To teach in order to lead others to faith is the task of every preacher and of each believer.

Theology is taught by God, teaches God, and leads to God.

If a thing can be done adequately by means of one, it is superfluous to do it by means of several; for we observe that nature does not employ two instruments [if] one suffices.

One cannot use an evil action with reference to a good intention.

Better to illuminate than merely to shine.

Not everything that is more difficult is more meritorious.

Characteristics which define beauty are wholeness, harmony and radiance.

Charity is the form, mover, mother and root of all the virtues.

Practical sciences proceed by building up; theoretical science by resolving into components.

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.

The last end of every maker, as such, is himself, for what we make we use for our own sake; and if at any time a man make a thing for the sake of something else, it is referred to his own good, whether his use, his pleasure, or his virtue.

The Eucharist is the Sacrament of Love; It signifies Love, It produces love. The Eucharist is the consummation of the whole spiritual life.

Nothing which implies contradiction falls under the omnipotence of God.

Wonder is the desire of knowledge.

One aspect of neighbourly love is that we must not merely will our neighbours good, but actually work to bring it about.

Likewise grace and glory are referred to the same genus, since grace is nothing other than a certain first beginning of glory in us.

I answer that, Even, as in the blessed in heaven there will be most perfect charity, so in the damned there will be the most perfect hate.

Humility is the mark of a genuine disciple.

Without doubt one is allowed to resist against the unjust aggressor to one's life, one's goods or one's physical integrity; sometimes, even 'til the aggressor's death... In fact, this act is aimed at preserving one's life or one's goods and to make the aggressor powerless. Thus, it is a good act, which is the right of the victim.

If there were some solitary or feral man, the passions of the soul would be sufficient for him; by them he would be conformed to things in order that he might have knowledge of them. But because man is naturally political and social, there is need for one man to make his conceptions known to others, which is done with speech. So significant speech was needed if men were to live together. Which is why those of different tongues do not easily live together.

Unbelief is the greatest of sins.