Shatapatha Brahmana 9.1.1.38

9.1.1.38

tebhyo daśa prācīḥ | daśa dakṣiṇā daśa pratīcīrdaśodīcīrdaśordhvā iti daśākṣarā virāḍvirāḍagnirdaśa diśo diśo 'gnirdaśa prāṇāḥ prāṇā agniryāvānagniryāvatyasya mātrā tāvataivainānetadannena prīṇāti

'To them (I stretch) ten (fingers) forwards, ten to the right, ten backwards, ten to the left, ten upwards,'--of ten syllables consists the Virâg, and Agni is Virâg; there are ten seasons, and Agni is the seasons; there are ten vital airs, and Agni is the vital airs: as great as Agni is, as great as is his measure, with so much food he thus gratifies them.