Thomas Aquinas & the Power of Pure Prayer

Purity of Heart

We study to seek truth, and Truth Himself declared to us, “Blessed are the pure of heart, for they shall see God” (Matt. 5:8). Only when our heart, our conscience, and our will are pure, free from the distractions of temptation and the stains of sin, can our intellects gaze clearly upon truth.

Prudence is the virtue that guides the moral virtues of temperance, fortitude, and justice, but it also depends on them. It is through the exercise of virtues such as self-control and courage that we can discipline our minds to focus on what is truly important and then act to achieve it. Moral virtue strengthens and sharpens our powers of understanding so that they may better “penetrate into the heart of things.” We will not achieve the heights of intellectual virtue, of knowing the true in the manner of St. Thomas Aquinas, without at the same time climbing and growing in the moral virtue of striving to seek only what is truly good.

St. Thomas was well aware of how temptations toward sexual impurity and other bodily sins can draw our hearts and minds away from the things that matter most. In writing about the “daughters” of the vice of acedia (or spiritual sloth) he declared, echoing Aristotle, that “those who find no joy in spiritual pleasures have recourse to pleasures of the body.”

Indeed, when Thomas as a young man had dedicated his life to preaching and teaching Christ’s gospel as a member of the new, humble Dominican Order, his biological brothers were so outraged that they captured him on the road to Paris and took him back to the family’s castle. There, his brothers explicitly endeavored to remove his mind from spiritual things through a powerful temptation to bodily pleasure. They introduced a beautiful young courtesan into his room, whereupon Thomas brandished a log from the fireplace and chased her out the door, making a sign of the cross on the door with the firebrand when he slammed it shut behind her! Pious legend reports that angels then came to his aid and gave him a girdle of chastity, whereupon he was never again tempted by sensual bodily pleasures, as he immersed himself totally in the joys of the intellect and the spirit.

Of course, we all have different bodies, temperaments, and dispositions, and some of us, by nature, suffer greater temptations to impurity than others do. As a young man, St. Augustine famously prayed that God would give him chastity, “but not yet.” St. Paul wrote of the war between the flesh and the spirit, and how easy it is for carnal, enfleshed human beings to leave undone the good things we want to do while doing the evil things that we hate (see Rom. 7:13–22), echoing Christ’s warning to Peter that in matters of temptation, “the spirit indeed is willing but the flesh is weak” (Matt. 26:41).

Singulars & Universals

Thomas has provided a rather abstract-sounding but exceedingly practical bit of advice that can go a long way toward helping the spirit conquer the flesh so that we can focus upon higher things: “Hence, the most effective remedy against intemperance is not to dwell on the consideration of singulars.”

This is a preview of How to Think Like Aquinas. Click image to learn more.

Lust, the most powerful challenge to the virtue of temperance and purity of heart, thrives on singulars, especially visual images of particular enticing bodies. Unfortunately, advertisers and the purveyors of popular media know this so well that we are perpetually bombarded by images purposely designed to arouse our lusts, be it on television shows and commercials, in movies, in newspapers and magazines, or plastered greater than life-size on unavoidable roadside billboards. What, then, are we to do?

St. Thomas suggests that we focus on the opposite of those “singulars” that we grasp with our senses as animals do; namely, we should turn our attention to the “universals” that only we humans can grasp through our God-given intellects. Instead of focusing on this or that particular woman, try focusing on “woman.”

The couple blessed with the sacrament of marriage can treat each other with special loving attention as singulars, but they, too, must love rather than lust, loving each other in the flesh, yet never seeing or using the other as mere flesh alone. St. Thomas was especially adept at practicing temperance because of his focus on the very highest of universals, the divine things of God.

Spiritual sloth, he wrote, paves the way for lust and intemperance, because he knew that “those who find no joy in spiritual things have recourse to pleasures of the body.” To curb lust, then, let us focus most on the highest things of God, from which flows love, not lust. The pure of heart, after all, will see God.

Regardless of the nature or intensity of our temptations, we also have access to the grace of God, the ultimate remedy for the bodily yearnings that pull us away from contemplation and spiritual joys. As Eastern Father St. John Climacus stated so well:

Do not imagine that you will overwhelm the demon of fornication by entering into an argument with him. Na­ture is on his side and he has the best of the argument. So the man who decides to struggle against his flesh and to overcome it by his own efforts is fighting in vain. The truth is that unless the Lord overturns the house of the flesh and builds the house of the soul, the man wishing to overcome it has watched and fasted for nothing. Offer up to the Lord the weakness of your nature. Admit your incapacity and, without your knowing it, you will win for yourself the gift of chastity.

Of course, it is not only sins of lust that can lead to an impure conscience. If we are to think like Aquinas, we must strive against all manner of sin, to build all manner of virtue, and to ask God to help us in battle; we must also thank Him when we emerge victorious. In fact, this leads us to Thomas’s next precept.

The Power of Prayer in Perfecting Our Thinking (and Doing)

Prayer is the Christian’s fundamental means of acquiring virtue: “If any of you lack wisdom, let him ask God, who gives to all men generously” (James 1:5). Indeed, St. Thomas clearly practiced what he preached and taught, crediting his vast learning more to prayer than to study!

Hear the words of Thomas’s close friend, Brother Reginald of Piperno, quoted at Thomas’s canonization proceedings: “When perplexed by a difficulty he would kneel and pray and then, on returning to his writing and dictation, he was accustomed to find that his thought had become so clear that it seemed to show him inwardly, as in a book, the words he needed.” Might we all develop such a prayerful practice to overcome writer’s (or studier’s) block!

Only in prayer do we make direct contact with that ultimate Teacher and Maker of all Truths, and that is why it should undergird all our studies.

Thomas notes that we reach truth in two ways. In the first way, we receive truth from outside ourselves, and to access such truths directly from God, prayer is our means. Indeed, he cites the words of Wisdom 7:7: “I called upon God, and the spirit of wisdom came upon me.” As far as gaining truths from other people, our means are hearing the spoken word and reading the Holy Scriptures. The second method in which we reach truth through our actions requires personal study and meditation.

Prayer then, is our God-given means of acquiring His wisdom. In expounding on the various acts of the virtue of religion, Thomas writes, “According to Cassiodorus, prayer (oratio) is spoken reason (oris ratio).” Speech and reason are powers of the intellect, so prayer is not an act of the lower powers of sensation we share with other animals, but of our uniquely human intellectual powers.

Prayer is the province of the rational animal, and that animal is man. Thomas notes that prayer starts with and is essentially “the raising up of one’s mind to God.” Further, the “parts” of prayer include supplications (humble requests) and thanksgiving for blessings God has provided.

Because Thomas knew well what Father Sertillanges has stated so elegantly — that “the light of God does not shine under your study lamp, unless your soul asks for it with persistent effort” — he even crafted a special prayer that he recited before studying. Here is a brief excerpt:

Ineffable Creator,
Who, from the treasures of Your wisdom,
have established three hierarchies of angels,
have arrayed them in marvelous order
above the fiery heavens,
and have marshaled the regions
of the universe with such artful skill . . .
grant to me keenness of mind,
capacity to remember,
skill in learning,
subtlety to interpret,
and eloquence of speech.
May You guide the beginning of my work,
direct its progress, and bring it to completion.

The lesson could not be clearer: if we are to think like Aquinas, then we must pray like him, too!


Editor’s note: This article is from a chapter in Dr. Vost’s How to Think Like Aquinaswhich is available from Sophia Institute Press.

image: By Nheyob [CC BY-SA 4.0 ], from Wikimedia Commons

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Dr. Kevin Vost, Psy D. is the author of Memorize the Faith, The Seven Deadly Sins, The One Minute Aquinasas well as numerous other books and articles. He has taught psychology at the University of Illinois at Springfield, Lincoln Land Community College, and MacMurray College. He is a Research Review Committee Member for American Mensa, which promotes the scientific study of human intelligence. You can find him at

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