Kauṣītaki (Śāṅkhāyana) Brāhmaṇa 9.2.16

9.2.16

tatho eva etad yajamāna etābhir eva sarvā aṣṭīr aśnute /

ix. 2. He recites for him as he is taken forth the three verses containing ‘forth’, ‘Forth the god with the thought divine.’ ‘Thee in the footstep of the sacrificial food’, he says ; the sacrificial food is this (earth), for in it he praises (īṭṭe) all. He praises him when deposited with the half verse containing (the word) ‘deposit’, ‘O All-knower, we deposit thee.’ He praises him when he has sat down with (the verses ) containing (the word) ‘sit’, ‘O Agni, of fair face, with all the gods’; ‘Sit, O Hotṛ, in thine own place, discerning’, and ‘The Hotṛ in the Hotṛ’s seat, well knowing.’ He concludes with (a verse ) containing the word ‘herald’, ‘Thou art a herald; thou also our protector from afar.’ He recites appropriate verses; what in the sacrifice is appropriate, that is perfect; verily (it serves) for the perfection of the sacrifice. Eight he recites; the Gāyatrī has eight syllables; Agni is connected with the Gāyatrī, and has the Gāyatrī as his metre; verily thus with his own metre they bring Agni forward. (He recites) the first thrice, the third thrice; they make up twelve; the year has twelve months; verily (they serve) to obtain the year. They repeated together make up eighteen Gāyatrī verses; verily by the metre it is connected with Agni. Of whatever even metre there are six , they make up a Gāyatrī; of whatever there are seven, an Uṣṇih, of whatever there are eight an Anuṣṭubh, of whatever there are nine a Bṛhatī, of whatever there are ten a Paṅkti, of whatever there are eleven a Triṣṭubh, of whatever there are twelve (syllables) a Jagatī.