4.29 Breath into breath Krishna speaks

अपाने जुह्वति प्राण प्राणेऽपानं तथाऽपरे
प्राणापानगती रुद्ध्वा प्राणायामपरायणाः

apāne juhvati prāṇaṁ prāṇe ’pānaṁ tathāpare
prāṇāpāna-gatī ruddhvā prāṇāyāma-parāyaṇāḥ
apare niyatāhārāḥ prāṇān prāṇeṣhu juhvati
sarve ’pyete yajña-vido yajña-kṣhapita-kalmaṣhāḥ

Others offer the outgoing breath into the incoming, and the incoming into the outgoing, holding both still, intent on the breath.

Explanation

Breath into breath.

The outgoing into the incoming, and the incoming into the outgoing, holding both still.

This is prāṇāyāma named as an offering rather than as a technique. The catalogue has now reached the most interior act available — and it is still called a sacrifice.

Going further

Verses 4.25 to 4.30 catalogue every kind of offering the tradition knew: to gods, into restraint, of the senses, of possessions, of austerity, of study, of the breath itself.

The list is doing something other than instructing. It is establishing that the form does not matter much — six wildly different practices, all called by the same name. What they share is the structure of giving something up without expecting a return, and the chapter is more interested in that structure than in any of the methods.

Word by word

apāne: the incoming breath
juhvati: offer
prāṇam: the outgoing breath
prāṇe: in the outgoing breath
apānam: incoming breath
tathā: also
apare: others
prāṇa: of the outgoing breath
apāna: and the incoming breath
gatī: movement
ruddhvā: blocking
prāṇa-āyāma: control of breath
parāyaṇāḥ: wholly devoted apare—others
niyata: having controlled
āhārāḥ: food intake
prāṇān: life-breaths
prāṇeṣhu: life-energy
juhvati: sacrifice
sarve: all
api: also
ete: these
yajña-vidaḥ: knowers of sacrifices
yajña-kṣhapita: being cleansed by performances of sacrifices
kalmaṣhāḥ: of impurities