Seventeen Quotes by St Thomas Aquinas (With References)

This page contains a collection of quotes by St Thomas Aquinas. These quotes are all genuine and details about the book, chapter number, and translation are included where applicable. Quotes that begin with a section of bold text are my personal favourites. Without further ado, here are seventeen quotes by St Thomas Aquinas:


All that I have written seems to me like straw compared to what has now been revealed to me.

– St Thomas Aquinas as quoted in J. A. Weisheipl, Friar Thomas d’Aquino, p. 322


Perhaps not everyone who hears this word “God” understands it to signify something than which nothing greater can be thought, seeing that some have believed God to be a body. Yet, granted that everyone understands that by this word “God” is signified something than which nothing greater can be thought, nevertheless, it does not therefore follow that he understands that what the word signifies exists actually, but only that it exists mentally.

– St Thomas Aquinas, Summa Theologica, I, 2, 1, trans. Fathers of the English Dominican Province


Whatever is in motion must be put in motion by another. If that by which it is put in motion be itself put in motion, then this also must needs be put in motion by another, and that by another again. But this cannot go on to infinity, because then there would be no first mover, and, consequently, no other mover; seeing that subsequent movers move only inasmuch as they are put in motion by the first mover; as the staff moves only because it is put in motion by the hand. Therefore it is necessary to arrive at a first mover, put in motion by no other; and this everyone understands to be God.

– St Thomas Aquinas, Summa Theologica, I, 2, 3, trans. Fathers of the English Dominican Province


Whence to us they cannot be certain, forasmuch as we know future contingent things as such; but (they are certain) to God alone, whose understanding is in eternity above time. Just as he who goes along the road, does not see those who come after him; whereas he who sees the whole road from a height, sees at once all travelling by the way.

– St Thomas Aquinas, Summa Theologica, I, 14, 13, trans. Fathers of the English Dominican Province


It is impossible that any evil, as such, should be sought for by the appetite, either natural, or animal, or by the intellectual appetite which is the will. Nevertheless evil may be sought accidentally, so far as it accompanies a good, as appears in each of the appetites.

– St Thomas Aquinas, Summa Theologica, I, 19, 9, trans. Fathers of the English Dominican Province


Some things there are which act, not from any previous judgment, but, as it were, moved and made to act by others; just as the arrow is directed to the target by the archer. Others act from some kind of judgment; but not from free-will, such as irrational animals; for the sheep flies from the wolf by a kind of judgment whereby it esteems it to be hurtful to itself: such a judgment is not a free one, but implanted by nature. Only an agent endowed with an intellect can act with a judgment which is free, in so far as it apprehends the common note of goodness; from which it can judge this or the other thing to be good. Consequently, wherever there is intellect, there is free-will.

– St Thomas Aquinas, Summa Theologica, I, 59, 3, trans. Fathers of the English Dominican Province


Knowledge is loved not that any good may come to it but that it may be possessed.

– St Thomas Aquinas, Summa Theologica, I, 60, 3, trans. Fathers of the English Dominican Province


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

– St Thomas Aquinas, Summa Theologica, I, 95, 2, trans. Fathers of the English Dominican Province


It is impossible for any created good to constitute man’s happiness. For happiness is the perfect good, which lulls the appetite altogether; else it would not be the last end, if something yet remained to be desired. … Hence it is evident that naught can lull man’s will, save the universal good. This is to be found, not in any creature, but in God alone. … Therefore God alone constitutes man’s happiness.

– St Thomas Aquinas, Summa Theologica, I-II, 2, 8, trans. Fathers of the English Dominican Province


A certain participation of Happiness can be had in this life: but perfect and true Happiness cannot be had in this life. …  Since happiness is a “perfect and sufficient good,” it excludes every evil, and fulfils every desire. But in this life every evil cannot be excluded. For this present life is subject to many unavoidable evils; to ignorance on the part of the intellect; to inordinate affection on the part of the appetite, and to many penalties on the part of the body. … Likewise neither can the desire for good be satiated in this life. For man naturally desires the good, which he has, to be abiding. Now the goods of the present life pass away; since life itself passes away, which we naturally desire to have, and would wish to hold abidingly, for man naturally shrinks from death. Wherefore it is impossible to have true Happiness in this life.

– St Thomas Aquinas, Summa Theologica, I-II, 5, 3, trans. Fathers of the English Dominican Province


Every action has goodness, in so far as it has being; whereas it is lacking in goodness, in so far as it is lacking in something that is due to its fulness of being; and thus it is said to be evil.

– St Thomas Aquinas, Summa Theologica, I-II, 18, 1, trans. Fathers of the English Dominican Province


If then reason or conscience err with an error that is involuntary, either directly, or through negligence, so that one errs about what one ought to know; then such an error of reason or conscience does not excuse the will, that abides by that erring reason or conscience, from being evil. But if the error arise from ignorance of some circumstance, and without any negligence, so that it cause the act to be involuntary, then that error of reason or conscience excuses the will, that abides by that erring reason, from being evil.

– St Thomas Aquinas, Summa Theologica, I-II, 19, 6, trans. Fathers of the English Dominican Province


The greatest of all pleasures consists in the contemplation of truth.

– St Thomas Aquinas, Summa Theologica, I-II, 38, 4, trans. Fathers of the English Dominican Province


As the Philosopher [Aristotle] says, “one knowledge is preferable to another, either because it is about a higher object, or because it is more certain.” Hence if the objects be equally good and sublime, that virtue will be greater which possesses more certain knowledge. But a virtue which is less certain about a higher and better object, is preferable to that which is more certain about an object of inferior degree. Wherefore the Philosopher says that “it is a great thing to be able to know something about celestial beings, though it be based on weak and probable reasoning”; and again that “it is better to know a little about sublime things, than much about mean things.” Accordingly wisdom, to which knowledge about God pertains, is beyond the reach of man, especially in this life, so as to be his possession: for this “belongs to God alone”: and yet this little knowledge about God which we can have through wisdom is preferable to all other knowledge.

– St Thomas Aquinas, Summa Theologica, I-II, 66, 5, trans. Fathers of the English Dominican Province


[Law] is nothing else than an ordinance of reason for the common good, made by him who has care of the community, and promulgated.

– St Thomas Aquinas, Summa Theologica, I-II, 90, 4, trans. Fathers of the English Dominican Province


The purpose of human law is to lead men to virtue, not suddenly, but gradually. Wherefore it does not lay upon the multitude of imperfect men the burdens of those who are already virtuous, namely, that they should abstain from all evil. Otherwise these imperfect ones, being unable to bear such precepts, would break out into yet greater evils.

– St Thomas Aquinas, Summa Theologica, I-II, 96, 2, trans. Fathers of the English Dominican Province


He who enters religion does not make profession to be perfect, but he professes to endeavor to attain perfection; even as he who enters the schools does not profess to have knowledge, but to study in order to acquire knowledge.

– St Thomas Aquinas, Summa Theologica, II-II, 186, 2, trans. Fathers of the English Dominican Province


Know of a quote that I’ve missed? Let me know in the comments below!

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