The knowledge of yourself will preserve you from vanity.

Hear the words of Miguel de Cervantes, father of Don Quixote and chronicler of human folly, who declared: “The knowledge of yourself will preserve you from vanity.” In this short phrase lies a truth profound and timeless: when a man knows himself—his limits as well as his gifts—he becomes immune to the poison of pride. For self-knowledge is the shield that guards the soul against the illusions of greatness falsely imagined, and against the hunger to be praised without merit.

The ancients taught this same wisdom. At the temple of Apollo in Delphi were carved the words: Know thyself. To obey this command was to walk the path of truth. For the man who knows himself—his strengths, his weaknesses, his virtues, his vices—will not be lifted too high by empty flattery, nor cast too low by false despair. He will walk steadily, unmoved by the storms of others’ opinions, rooted in the soil of reality. Vanity has no power over him, for he sees himself as he truly is.

Consider the tale of Julius Caesar. His genius was real, his victories many, but in time his pride overcame his wisdom. He listened too much to the chorus of flatterers, and in believing himself greater than all, he fell to the daggers of those who once served him. Contrast this with Marcus Aurelius, the philosopher-emperor, who kept a book of meditations reminding himself each day of his mortality, his faults, and his duty to serve. Caesar, blinded by vanity, fell. Aurelius, guarded by self-knowledge, endured as one of Rome’s most honored rulers.

Cervantes himself knew the peril of pride. In Don Quixote, he gave the world a knight who mistook windmills for giants, who lived not in truth but in delusion. Though noble of heart, Don Quixote’s failure to see himself clearly made him a figure of both comedy and tragedy. Through this tale, Cervantes warns us that without self-knowledge, even good intentions may be twisted into folly. The man who does not see himself clearly is as one wandering in a dream, unable to walk firmly upon the earth.

Yet let us not mistake self-knowledge for self-contempt. To know oneself truly is not to despise one’s weaknesses, but to understand them, to master them, and to grow. Just as a craftsman must know the flaws and strengths of his material before shaping it, so must a man know his own nature before he can refine it. Self-knowledge is not the death of aspiration—it is the root of true greatness, for only the one who knows himself can rise without being destroyed by vanity.

The meaning, then, is clear: self-knowledge is both compass and anchor. It guides us away from the illusions of grandeur and preserves us from the snares of arrogance. It allows us to accept praise without being consumed by it, and to endure criticism without being broken by it. Vanity feeds upon ignorance of the self, but when the soul is lit by true understanding, pride loses its sting.

The lesson is for us all: seek to know yourself. Examine your motives, your desires, your strengths, and your failings. Reflect daily, as Marcus Aurelius did. Listen to both friend and critic, and weigh their words not by pride, but by truth. Humble yourself before your own imperfections, and use that humility to grow. In this way, you will walk the path Cervantes spoke of—guarded from vanity, strengthened by truth, and prepared to lead with honor.

Therefore, let your practice be this: when you are praised, ask yourself if it is deserved. When you are criticized, ask yourself what may be learned. In moments of triumph, remind yourself of your limits; in moments of failure, remember your strengths. For as Cervantes declared, the knowledge of yourself will preserve you from vanity—and in that preservation lies the path to wisdom, dignity, and peace.