Śatapatha Brāhmaṇa ("of a hundred paths") 2.6.2.12

2.6.2.12

athāpasalavi triḥ pariyanti | savyānūrūnupāghnānāstryambakaṃ yajāmahe sugandhim puṣṭivardhanam urvārukamiva bandhanānmṛtyormukṣīya māmṛtādityāśīrevaiṣaitasya karmaṇa āśiṣamevaitadāśāsate tadu hyeva śamiva yo mṛtyormucyātai nāmṛtāttasmādāha mṛtyormukṣīya māmṛtāditi

They then walk thrice round the altar not sun-wise, beating their left thighs (with the right hand), with the text (Vâg. S. III, 60 a), 'We worship Tryambaka, the fragrant increaser of prosperity. Even as a gourd (is severed) from its stem, so may I be severed from death, not from immortality!' This is the prayer for blessing at this performance: thereby they invoke a blessing (upon the Sacrificer), for verily blessed is he who shall be severed from death, not from immortality. That is why he says, 'May I be severed from death, not from immortality.'