Thomas Aquinas quotes:

The truth of our faith becomes a matter of ridicule among the infidels if any Catholic, not gifted with the necessary scientific learning, presents as dogma what scientific scrutiny shows to be false.

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.

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

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.

There is nothing on this earth more to be prized than true friendship.

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.

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

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.

It is clear that he does not pray, who, far from uplifting himself to God, requires that God shall lower Himself to him, and who resorts to prayer not to stir the man in us to will what God wills, but only to persuade God to will what the man in us wills.

How can we live in harmony? First we need to know we are all madly in love with the same God.

It is requisite for the relaxation of the mind that we make use, from time to time, of playful deeds and jokes.

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.

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.

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.

There is but one Church in which men find salvation, just as outside the ark of Noah it was not possible for anyone to be saved.

Friendship is the source of the greatest pleasures, and without friends even the most agreeable pursuits become tedious.

Reason in man is rather like God in the world.

Pray thee, spare, thyself at times: for it becomes a wise man sometimes to relax the high pressure of his attention to work.

All the efforts of the human mind cannot exhaust the essence of a single fly.

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.

Well-ordered self-love is right and natural.

Wonder is the desire for knowledge.

Law is nothing other than a certain ordinance of reason for the common good, promulgated by the person who has the care of the community.

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.

Faith has to do with things that are not seen and hope with things that are not at hand.

The highest manifestation of life consists in this: that a being governs its own actions. A thing which is always subject to the direction of another is somewhat of a dead thing.

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

Because we cannot know what God is, but only what He is not, we cannot consider how He is but only how He is not.

It is necessary to posit something which is necessary of itself, and has no cause of its necessity outside of itself but is the cause of necessity in other things. And all people call this thing God.

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.

Law; an ordinance of reason for the common good, made by him who has care of the community.

To one who has faith, no explanation is necessary. To one without faith, no explanation is possible.

Happiness is secured through virtue; it is a good attained by man's own will.

Most men seem to live according to sense rather than reason.

Because philosophy arises from awe, a philosopher is bound in his way to be a lover of myths and poetic fables. Poets and philosophers are alike in being big with wonder.

Human salvation demands the divine disclosure of truths surpassing reason.

It is not theft, properly speaking, to take secretly and use another's property in a case of extreme need: because that which he takes for the support of his life becomes his own property by reason of that need

Better to illuminate than merely to shine to deliver to others contemplated truths than merely to contemplate.

The principal act of courage is to endure and withstand dangers doggedly rather than to attack them.

An angel can illumine the thought and mind of man by strengthening the power of vision and by bringing within his reach some truth which the angel himself contemplates.

A person is disposed to an act of choice by an angel ... in two ways. Sometimes, a man's understanding is enlightened by an angel to know what is good, but it is not instructed as to the reason why ... But sometimes he is instructed by angelic illumination, both that this act is good and as to the reason why it is good.

Sorrow can be alleviated by good sleep, a bath and a glass of wine.

If the highest aim of a captain were to preserve his ship, he would keep it in port forever.

The things that we love tell us what we are.

Just as in one man there is one soul and one body, yet many members; even so the Catholic Church is one body, having many members. The soul that quickens this body is the Holy Spirit; and therefore in the Creed after confessing our belief in the Holy Spirit, we are bid to believe in the Holy Catholic Church.

The celestial bodies are the cause of all that takes place in the sublunar world.

Clearly the person who accepts the Church as an infallible guide will believe whatever the Church teaches.

Whenever God wakes in us, our thinking becomes clear - nothing is missing.

In the life of the body a man is sometimes sick, and unless he takes medicine, he will die. Even so in the spiritual life a man is sick on account of sin. For that reason he needs medicine so that he may be restored to health; and this grace is bestowed in the Sacrament of Penance.

The minister to whom confession is made is the delegate of Christ, Who is the Judge of the living and the dead.

Better to illuminate than merely to shine, to deliver to others contemplated truths than merely to contemplate.

Those who are more adapted to the active life can prepare themselves for contemplation in the practice of the active life, while those who are more adapted to the contemplative life can take upon themselves the works of the active life so as to become yet.

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.

Down in adoration falling, Lo! the sacred Host we hail; Lo! o'er ancient forms departing, Newer rites of grace prevail; Faith for all defects supplying, Where the feeble senses fail.

Temperance is simply a disposition of the mind which binds the passion.

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

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.

The world of pure spirits stretches between the divine nature and the world of human beings; because divine wisdom has ordained that the higher should look after the lower, angels execute the divine plan for human salvation: they are our guardians, who free us when hindered and help to bring us home.

By the divine providence [animals] are intended for man's use... Hence it is not wrong for man to make use of them, either by killing or in any other way whatsoever.

By nature all men are equal in liberty, but not in other endowments.

The Blessed Eucharist is the perfect Sacrament of the Lord's Passion, since It contains Christ Himself and his Passion.

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

Love is a binding force, by which another is joined to me and cherished by myself.

My only regret in life is that I did not drink more Champagne - John Maynard Keynes Sorrow can be alleviated by good sleep, a bath and a glass of good wine

Love takes up where knowledge leaves off.

The custom of the Church has very great authority and ought to be jealously observed in all things.

A man does not always choose what his guardian angel intends.

Love must precede hatred, and nothing is hated save through being contrary to a suitable thing which is loved. And hence it is that every hatred is caused by love.

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.

The celebration of Holy Mass is as valuable as the death of Jesus on the cross.

If someone knows from experience that daily Communion increases fervor without lessening reverence, then let him go every day. But if someone finds that reverence is lessened and devotion not much increased, then let him sometimes abstain, so as to draw near afterwards with better dispositions.

If, then, you are looking for the way by which you should go, take Christ, because He Himself is the way.

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

As mariners are guided into port by the shining of a star, so Christians are guided to heaven by Mary.

Without sanctifying grace it is not possible to refrain long from mortal sin.

Venial sin becomes mortal sin when one approves it as an end. . .

I cannot understand how anyone conscious of mortal sin can laugh or be merry.

It must be said that charity can, in no way, exist along with mortal sin.

To pretend angels do not exist because they are invisible is to believe we never sleep because we don't see ourselves sleeping.

To be united to God in unity of person was not fitting to human flesh, according to its natural endowments, since it was above his dignity; nevertheless, it was fitting that God, by reason of his infinite goodness, should unite it to himself for human salvation.

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

Nothing which implies contradiction falls under the omnipotence of God.

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.

Jesus Lord, kind Pelican, Cleanse my filth with Thy blood, One drop of which can save The whole world from all its sin

A man should remind himself that an object of faith is not scientifically demonstrable, lest presuming to demonstrate what is of faith, he should produce inconclusive reasons and offer occasion for unbelievers to scoff at a faith based on such ground.

The same fire" (which he decides to be material) " torments the damned in hell and the just in purgatory...The least pain in purgatory exceeds the greatest in this life.

Being born he have himself as our Companion, Eating with us he gave himself as Food, Dying He became our Ransom, Reigning he gives himself as our Reward

A man has free choice to the extent that he is rational.

Justice is a certain rectitude of mind whereby a man does what he ought to do in the circumstances confronting him.

Man has free choice, or otherwise counsels, exhortations, commands, prohibitions, rewards and punishments would be in vain.

Honor is due to God and to persons of great excellence as a sign of attestation of excellence already existing; not that honor makes them excellent.

The soul is like an uninhabited worldthat comes to life only whenGod lays His headagainst us.

Mercy without justice is the mother of dissolution; justice without mercy is cruelty.

knowledge depends on the mode of the knower; for what is known is in the knower according to the measure of his mode

The study of truth requires a considerable effort - which is why few are willing to undertake it out of love of knowledge - despite the fact that God has implanted a natural appetite for such knowledge in the minds of men.

The blessed in the kingdom of heaven will see the punishments of the damned, in order that their bliss be more delightful for them.

Friendship makes you feel as one with your friend.

Three things are necessary for the salvation of man: to know what he ought to believe; to know what he ought to desire; and to know what he ought to do.

We must love them both, those whose opinions we share and those whose opinions we reject, for both have labored in the search for truth, and both have helped us in finding it.

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

Greed is a sin against God, just as all mortal sins, in as much as man condemns things eternal for the sake of temporal things,

A scrap of knowledge about sublime things is worth more than any amount about trivialities.

We set forth our petitions before God, not in order to make known to Him our needs and desires, but rather so that we ourselves may realize that in these things it is necessary to turn to God for help.

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.

Grant me, O Lord my God, a mind to know you, a heart to seek you, wisdom to find you, conduct pleasing to you, faithful perseverance in waiting for you, and a hope of finally embracing you. Amen.

When the devil is called the god of this world, it is not because he made it, but because we serve him with our worldliness.

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

Man cannot live without joy; therefore when he is deprived of true spiritual joys it is necessary that he become addicted to carnal pleasures.

We can't have full knowledge all at once. We must start by believing; then afterwards we may be led on to master the evidence for ourselves.

Beware of the person of one book.

To bear with patience wrongs done to oneself is a mark of perfection, but to bear with patience wrongs done to someone else is a mark of imperfection and even of actual sin.

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.

"The Jews should not be allowed to keep what they have obtained from others by usury; it were best that they were compelled to worked so that they could earn their living instead of doing nothing but becoming avaricious."

...[sacred] doctrine is especially based upon arguments from authority, inasmuch as its principles are obtained by revelation: thus we ought to believe on the authority of those to whom the revelation has been made. Nor does this take away from the dignity of this doctrine, for although the argument from authority based on human reason is the weakest, yet the argument from authority based on divine revelation is the strongest.

[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.

A man's heart is right when he wills what God wills.

A song is the exultation of the mind dwelling on eternal things, bursting forth in the voice.

A thing is lovable according as it is good. But God is infinite good. Therefore He is infinitely lovable.

Affirmative precepts are distinguished from negative whenever one is not comprised in the other; thus, that of honoring parents does not comprise that of not killing, and vice versa.

All men are equal in nature, and also in original sin. It is in the merits and demerits of their actions that they differ.