Famous Thomas Aquinas Quotes Explained
Thomas Aquinas was a 13th-century Italian Dominican friar and philosopher, the most influential figure of medieval scholasticism. Aquinas's <em>Summa Theologiae</em> is one of the longest sustained arguments in Western philosophy; his shorter prayers and hymns have nearly equal liturgical reach. Below are eight of the most-quoted lines.
Attributed to Thomas Aquinas:
“There is nothing on this earth more to be prized than true friendship.”
What it means
From the Summa Theologiae, where Aquinas treats friendship (amicitia) as the highest form of natural human goodness, and charity (caritas) as a kind of friendship with God. The line places companionship between virtuous persons at the top of the order of earthly goods.
Attributed to Thomas Aquinas:
“The things that we love tell us what we are.”
What it means
Attributed to Aquinas in the homiletic tradition. The substance reflects his account of love in the Summa: every love is a movement of the will toward what it perceives as good, so the objects one loves disclose what one has actually judged to be valuable, regardless of what one says.
Attributed to Thomas Aquinas:
“Justice is a certain rectitude of mind whereby a man does what he ought to do in the circumstances confronting him.”
What it means
From the Summa Theologiae, Second Part, Q. 58, the treatise on justice. Aquinas inherits Aristotle's definition of justice as a settled disposition and refines it for Christian use: justice is the will's habitual rectitude in giving each person what is owed in the relevant circumstance.
Attributed to Thomas Aquinas:
“By nature all men are equal in liberty, but not in other endowments.”
What it means
From Aquinas's commentary on Aristotle's Politics and echoed in the Summa. The position carves out the medieval Christian compromise: a metaphysical equality before God that grounds basic moral duties, paired with practical inequalities of role, gift, and authority within social life.
Attributed to Thomas Aquinas:
“Faith has to do with things that are not seen, and hope with things that are not at hand.”
What it means
From the Summa Theologiae, Second Part, in Aquinas's treatise on the theological virtues. The two halves of the line distinguish the structure of faith (cognitive, directed at invisible truths) from the structure of hope (volitional, directed at future goods).
“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.”
Tria sunt homini necessaria ad salutem: scilicit scientia credendorum, scientia desiderandorum, et scientia operandorum.
What it means
From Aquinas's short catechetical work De Duobus Praeceptis Caritatis. The three knowledges correspond to the three theological virtues: the Creed (faith) tells what to believe, the Lord's Prayer (hope) what to desire, and the Commandments (charity) what to do.
Attributed to Thomas Aquinas:
“Wonder is the desire for knowledge.”
What it means
From the Summa Theologiae, Q. 32, where Aquinas analyses wonder (admiratio) as the affective beginning of inquiry. Wonder is the recognition that an effect exceeds its evident cause, which provokes the will to seek the unknown cause. The position is inherited from Aristotle's Metaphysics.
“Anything done against faith or conscience is sinful.”
Commentary on Romans , cap 14, I 3
What it means
From the Summa Theologiae, where Aquinas addresses the binding force of conscience. Conscience, even when in error, has authority over the will: acting against one's settled moral judgement is wrong even when the judgement itself happens to be mistaken.