Śatapatha Brāhmaṇa ("of a hundred paths") 10.4.3.2

10.4.3.2

eṣa u evāntakaḥ eṣa hi martyānāmahorātrābhyāmāyuṣo'ntaṃ gacatyatha mriyante tasmādeṣa evāntakaḥ sa yo haitamantakam mṛtyuṃ saṃvatsaraṃ veda na hāsyaiṣa purā jaraso'horātrābhyāmāyuṣo'ntaṃ gacati sarvaṃ haivāyureti

And he, indeed, is the Ender, for it is he who, by day and night, reaches the end of the life of mortals, and then they die: therefore he is the Ender, and whosoever knows this Year, Death, the Ender, the end of his life that (Year) does not reach, by day and night, before old age, and he attains his full (extent of) life.