In this context, the term tat-purusha refers to that entity which is the atman—an eternal, immortal, and sinless essence representing the supreme power, often identified with Brahma.

The Divine Essence: Unveiling the Atman and Brahma

In this context, the term tat-purusha refers to that entity which is the atman—an eternal, immortal, and sinless essence representing the supreme power, often identified with Brahma. This meaning is clarified in the text where Prajapati tells his disciples: “The purusha that we see in the eye is the atman. Yes,” he added, “this is Brahma, the immortal being who knows no sin” (source: link txt, page: 674). Here, it is emphasized that tat-purusha is something that manifests as the atman—a bearer of purity and perfection—making it a fundamental principle in understanding the divine and eternal nature of reality.

Supporting citation(s):
“Then Indra from the realm of the Devas and Virochana from the realm of the Asuras set out on their journey and, without conspiring, came to Prajapati with kindling (for sacrifice) in hand. They remained his disciples for thirty-two years.

Prajapati said to them: ‘With what purpose did you remain here?

’ They replied: ‘Revered one! It is said that one must seek, must strive to know the atman, for which there is no sin… etc. Wishing to know it, we stayed here.’ Prajapati said to them: ‘The purusha that we see in the eye is the atman. Yes,’ he added, ‘this is Brahma, the immortal being who is without sin’” (source: link txt, page: 674).