Bhagavad Gita · Chapter 4: Knowledge and the Renouncing of Action

Bhagavad Gita 4.29

apāne juhvati prāṇaṃ prāṇe'pānaṃ tathāpare | prāṇāpānagatī ruddhvā prāṇāyāmaparāyaṇāḥ ||

Others, devoted to breath control, offer the outward breath into the inward breath and the inward into the outward, restraining the movement of both.

Modern context

The breath can itself be an offering. This verse describes pranayama: the outgoing breath is poured into the incoming, the incoming into the outgoing, and in between the breath is held still. The practical basis is known to anyone who has taken a slow breath before a difficult moment. Breath and mind move together. An agitated mind breathes fast and shallow, and slowing the breath on purpose calms the mind in turn. The breath is the one bodily rhythm we can easily take in hand, and through it we can reach the mind.