Śatapatha Brāhmaṇa ("of a hundred paths") 9.3.2.8

9.3.2.8

dvādaśasu kalpayati | dvādaśa māsāḥ saṃvatsaraḥ saṃvatsaro 'gniryāvānagniryāvatyasya mātrā tāvataivainametadannena prīṇātyatho tāvataivainametadannenābhiṣiñcati caturdaśasu kalpayatyaṣṭāsu kalpayati daśasu kalpayati trayodaśasu kalpayati

In twelve (things) he causes them to prosper, the year consists of twelve months, and Agni is the year: as great as Agni is, as great as is his measure, by so much food he thus gratifies him, and by so much food he thus consecrates him. In fourteen he causes them to prosper; in eight he causes them to prosper; in ten he causes them to prosper; in thirteen he causes them to prosper.