This prāṇa is born from the Ātman. As the shadow is spread over a person, so (prāṇa) is spread over This (Ātman). It comes to this body by the action of the mind.

This verse answers the third question of the Praśna Upaniṣad: “Where does prāṇa arise from?” The answer is profound: prāṇa emanates from the Ātman itself.

Ātmana eṣa prāṇo jāyate — this prāṇa is born from the Ātman. Prāṇa is not a separate force that enters us from outside. It is an emanation, a projection of the Self. Just as the sun emits rays, the Ātman emits prāṇa.

Yathā puruṣe chāyā — as the shadow of a person. The metaphor is precise: the shadow depends completely on the person but is not the person. It has no independent existence. Thus prāṇa depends on the Ātman but is not identical to it.

Etasminn etad ātatam — it is spread over This. Prāṇa spreads over the Ātman like a veil, like a projection. It cannot exist without its source, but neither is it separable from it.

Manokṛtenāyāty asmin śarīre — it comes to this body by the action of the mind. Here is the mechanism: the mind (manas) is the intermediary. Mental desires (saṅkalpa) attract prāṇa to incarnate in a particular body.

For the yogī, this teaching is fundamental: the prāṇa we work with in prāṇāyāma is not simply air or physical energy. It is the shadow of the Ātman, the closest manifestation of the Self in the world of form. To work with prāṇa is to work with something intimately connected to our deepest nature.