अपरे नियताहाराः प्राणान्प्राणेषु जुह्वति।
सर्वेऽप्येते यज्ञविदो यज्ञक्षपितकल्मषाः।।4.30।।
4.29. - 4.30. [Some sages] offer the prana into the apana; like-wise others offer the apana into the prana. Having controlled both the courses of the prana and apana, the same sages, with their desire fulfilled by the above activities, and with their food restricted, offer the pranas into pranas. All these persons know what sacrifices are and have their sins destroyed by sacrifices.
4.29-30 Apane etc. Apare etc. Prana (1st) : the arising one i.e., the nada which has, as its end, that one where the first syllabic instance of Pranava dissolves. Into the apana : into what sets down, and is of the nature of entering inot the Svananda. They offer : Thus is the svadhyaya of the nature of the firmness of the body is described. What sets down, some [sages] established on what rises up, so that the pupils self (mind) may learn the processes of sending out and drawing in [the vital airs]. By [thus] uniting these two, they bestow emanciaption on their own Self and on the Self of the pupils; and they, on that account, remain with their mind firmly established on the svadhyaya-sacrifice full of Svananda (i.e., Nijananda) and Parananda - a svadhyaya of the nature of examining, enlightening, entering and uniting [the prana nad apana] in their own Self and in the Self of the pupils. That is why the process of filling [the vital air] in has been first mentioned; and the process of emptying the same out at the last. Further, the process of the inward turning of the act of enjoying objects, is suggested by the first arter of the verse (29), and by the second arter the act of coming out for enjoying the objects through the process of having the supreme state-of-bodylessness. Therefore, the performers of the sacrifice of wisdom are not different from the performers of the svadhyaya-sacrifice. The same sages have the desries of their own and of their pupils fulfilled on account of their thorough practice of the said activity; control both the said paths, restrict their food viz., enjoyment of objects; and offer pranas into the pranas, i.e, they offer, by means of the ietude at the stage of stopping [the vital air], the rising of all the mental modifications into the splendour of rising waves of Parananda and Nirananda. All these persons know the truth (or nature) of hte sacrifices, starting from the material-sacrifice upto the wisdom-sacrifice; only by that means they have eradicated their sins; that is to say, they have uprooted the mighty delusion with its roots, made of mental impressions of duality.
Apare niyataahaaraah praanaan praaneshu juhwati; Sarve’pyete yajnavido yajnakshapita kalmashaah.
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