muṇḍaka upaniṣad - prathama muṇḍaka, dvitīya kāṇḍaḥ

This is the Truth: the sacred rites that the seers perceived in the Vedic hymns were extensively practiced in the Treta age. Perform them constantly, you who long for the Truth; this is your path to the world of virtuous deeds.

When the sacrificial fire is well-kindled and the flames flicker, let the sacrificer offer the oblations into the fire between the two portions of clarified butter.

If a man's Agnihotra sacrifice is not accompanied by the prescribed rites—without the new-moon and full-moon sacrifices, without the four-monthly sacrifices, without the harvest offering, without guests, or without the Vaisvadeva offering—or if it is performed incorrectly, it destroys his seven worlds.

Kali (the black), Karali (the terrifying), Manojava (the swift as thought), Sulohita (the deep red), Sudhumravarna (the smoky-colored), Sphulingini (the sparkling), and Visvaruchi (the all-bright) are the seven flickering tongues of the fire.

He who performs his sacrifices at the proper time in these flickering flames, the offerings carry him on the rays of the sun to where the one Lord of all the gods resides.

"Come! Come!" the radiant offerings call to the sacrificer, carrying him on the rays of the sun while praising him with pleasant words, saying, "This is your holy world of Brahman, earned by your good deeds."

Frail indeed are these sacrificial rafts, the eighteen forms of karma, in which the lower work is described. Fools who applaud this as the highest good fall again into the cycle of old age and death.

Living in the depths of ignorance, yet wise in their own conceit, the deluded wander about afflicted, like blind men led by one who is himself blind.

Dwelling in various ways in ignorance, the immature believe they have attained their goal. Because these performers of action do not understand the Truth due to attachment, they become miserable and fall when their worlds are exhausted.

Considering sacrifices and works of public utility to be the highest, these deluded people know no other path to the good. Having enjoyed the fruits of their deeds in the heights of heaven, they return to this world or one even lower.

Those who live in the forest, practicing penance and faith, who are tranquil, wise, and subsist on alms, depart through the path of the sun, freed from all impurities, to where that immortal and imperishable Being dwells.

Having scrutinized the worlds won by karma, a seeker should attain detachment, realizing that nothing that is created can produce the Uncreated. To understand that Supreme Reality, one should approach, with sacrificial fuel in hand, a teacher who is well-versed in the scriptures and established in Brahman.

To that seeker who has approached him appropriately, whose mind is perfectly tranquil and who is endowed with self-control, the wise teacher truly imparts the knowledge of Brahman, through which one realizes the eternal and unchanging Truth.