गोविन्द भाष्य (श्रील बलदेव विद्याभूषण - अचिन्त्यभेदाभेद वेदान्त ब्रह्मसूत्र भाष्य सटीक)

Adhikaraṇa 5
The Principal Prāṇa (Life-Force) Is Not Air
Introduction by Śrīla Baladeva Vidyābhūṣaṇa
Now the nature of the principal prāṇa (life-force) will be examined.
Saṁśaya (doubt): is the principal prāṇa air alone, the vibration of air, the
activities of air, or a condition of air when it goes to another place? Which is it?
Pūrvapakṣa (the opponent speaks): It is the external element of air. This is
confirmed in the following statement of Bṛhad-āraṇyaka Upaniṣad (3.1.5):
yo 'yaṁ prāṇaḥ sa vāyuḥ
"The prāṇa is air."
Or, perhaps the principal prāṇa is the activities of air, the inhalation and
exhalation of breath. In this way it is proved that the principal prāṇa is air.
Siddhānta (conclusion): In the following words the author of the sūtras gives
His conclusion.
Sūtra 9
na vāyu-kriye pṛthag upadeśāt
na—not; vāyu—air; kriye—action; pṛthak—different; upadeśāt—because of the
teaching.
It is neither air nor the activities of air, because the teaching is that it is
different.