Śatapatha Brāhmaṇa ("of a hundred paths") 10.2.6.9

10.2.6.9

bahubhirha vai yajñaiḥ ekamaharekā rātrirmitā sa ya evaikaśatavidhaṃ vidhatte yo vā śataṃ varṣāṇi jīvati sa haivainadaddhātamāmāpnotyeṣa vā ekaśatavidhaṃ vidhatte ya enaṃ saṃvatsaraṃ bibharti tasmādenaṃ saṃvatsarabhṛtameva cinvītetyadhidevatam

Only by many sacrifices, indeed, is a single day, or a single night (of life) gained; and only he who builds the one hundred and one-fold (altar), or he who lives a hundred years, is certain of his attaining to that immortal (life). But he, indeed, builds a one hundred and one-fold (altar) who carries him (Ukhya Agni) for a year: hence one should only build (an altar for) such an (Agni) who has been carried for a year. Thus much as to the deity.