Śatapatha Brāhmaṇa ("of a hundred paths") 10.2.6.19

10.2.6.19

annādvā aśanāyā nivartate pānātpipāsā śriyai pāpmā jyotiṣastamo'mṛtānmṛtyurni ha vā asmādetāni sarvāṇi vartante'pa punarmṛtyuṃ jayati sarvamāyureti ya evaṃ veda tadetadamṛtamityevāmutropāsītāyuritīha prāṇa iti haika upāsate prāṇo'gniḥ prāṇo'mṛtamiti vadanto na tathā vidyādadhruvaṃ vai tadyatprāṇastaṃ te viṣyāmyāyuṣo na madhyāditi hyapi yajuṣābhyuktaṃ tasmādenadamṛtamityevāmutropāsītāyuritīha tatho ha sarvamāyureti

Now, hunger ceases through food, thirst through drink, evil through well-being (goodness), darkness through light, and death through immortality; and, in truth, whosoever knows this from him all these pass away, and he conquers recurring death, and attains the whole (perfect) life. And let him hold this to be immortality in yonder world and life here below. Some, indeed, hold it to be breath, saying, 'The breath is fire, the breath is the immortal;' but let him not believe this, for something uncertain is breath. And regarding this it has also been said in the Yagus (Vâg. S. XII, 65), 'That (bond) of thine I unloose, as from the middle of Âyus (life):' let him therefore hold it to be immortality in yonder world, and life here below, and thus, indeed, he attains the whole life.