As birds go to a tree to rest, thus, verily, all this rests in the Supreme Self.

The metaphor of birds (vayāṃsi) perching on a tree (vṛkṣa) to rest (sampratiṣṭhante) is one of the most beloved in the Upaniṣadic tradition. Birds spend the day flying everywhere, but at dusk they return to the tree to rest.

Thus, all beings — in waking we wander through the world, active, seeking, consuming; but in deep sleep, or in death, or in liberation, we all return to the Supreme Self (para ātmani), the tree from which we came.

This is pratyāhāra (withdrawal of the senses) on a cosmic scale. All that is manifested has its origin and its end in the Self. Yoga is the art of making this withdrawal consciously, in life, to attain liberation.

The Ātman is the home, the refuge, the tree where the birds of the senses can rest eternally.