Kaṭha Upaniṣad · 2.3.8

अव्यक्तात्तु परः पुरुषो व्यापकोऽलिङ्ग एव च । यं ज्ञात्वा मुच्यते जन्तुरमृतत्वं च गच्छति ॥ ८ ॥

avyaktāttu paraḥ puruṣo vyāpako'liṅga eva ca | yaṃ jñātvā mucyate janturamṛtatvaṃ ca gacchati || 8 ||

Beyond the Unmanifest is the Puruṣa, the all-pervading one, without any sign. Knowing Him, the chained being is liberated and attains immortality.

The puruṣa (Supreme Being, cosmic Person) is avyaktāt paraḥ (beyond the unmanifest). He is vyāpaka (penetrating, omnipresent), the consciousness that permeates all without being limited by anything. He is aliṅga (without sign), without attributes that can point to Him or describe Him.

The jantu (chained being, creature) who knows this puruṣa is mucyate (liberated) from his chains. The amṛtatva (immortality) is not an infinite duration in time, but the realization of the eternal nature beyond time. It is not that we live forever; it is that we discover we were never born.

This is the goal of yoga: to know what cannot be known by the senses, mind, or intellect. When all instruments of knowledge fall silent, that which remains as the silent witness is the puruṣa. In that direct knowledge, without conceptual mediation, lies final liberation.