kaṭhopaniṣad - adhyāya 1, vallī 3

There are two who drink the fruits of their deeds in the world of righteousness, having entered the secret cave of the heart, the highest abode. Those who know Brahman, as well as those householders who have performed the triple Nachiketa sacrifice and the five sacred fires, describe them as light and shadow.

We may master that Nachiketa fire, which is the bridge for those who perform sacrifices, and which is also the supreme, imperishable Brahman for those who wish to cross over to the fearless shore.

Know the Atman as the lord of the chariot, the body as the chariot itself, the intellect as the charioteer, and the mind as the reins.

The senses are the horses, and the objects of the senses are the paths upon which they travel. The wise say that the Atman, when united with the body, senses, and mind, is the enjoyer.

He who is devoid of right knowledge and whose mind is always unrestrained—his senses are out of control, like the unruly horses of a charioteer.

He who possesses right knowledge and whose mind is always restrained—his senses are under control, like the well-trained horses of a charioteer.

He who is devoid of right knowledge, thoughtless, and always impure, does not reach that supreme state and continues to cycle through birth and death.

He who possesses right knowledge, who is thoughtful and always pure, reaches that state from which he is not born again.

The person who has the intellect as the charioteer and the mind as the well-controlled reins reaches the end of the journey, which is the supreme abode of the All-Pervading One.

Beyond the senses are the objects; beyond the objects is the mind; beyond the mind is the intellect; and beyond the intellect is the Great Self.

Beyond the Great Cosmic Intellect (Mahat) is the Unmanifest (Avyakta), and beyond the Unmanifest is the Cosmic Being (Purusha). Nothing exists beyond the Purusha; He is the culmination, He is the supreme goal.

This Atman, hidden in all beings, does not shine forth to the common eye; but It is perceived by the seers of subtle things through a sharp and subtle intellect.

The wise man should merge his speech into the mind, his mind into the discriminating intellect, his intellect into the Great Self, and that Great Self into the Self of Peace.

Arise! Awake! Approach the great ones and learn. The path is as sharp as a razor’s edge, difficult to traverse, and hard to tread—so the wise declare.

He who realizes that which is soundless, touchless, formless, undecaying, and also tasteless, eternal, and scentless; that which is beginningless, endless, and beyond the Great Cosmic Intellect—he is delivered from the jaws of death.

The wise man who hears and recounts this eternal story of Nachiketa, as told by Death, is glorified in the world of Brahman.

He who recites this supreme secret before an assembly of the wise, or during a ritual in honor of the ancestors, attains infinite merit. He attains infinite merit.