Śatapatha Brāhmaṇa ("of a hundred paths") 6.4.2.6

6.4.2.6

athaite triṣṭubhā uttare bhavataḥ | ātmā vai triṣṭubātmānamevāsyaitābhyāṃ saṃskaroti sīda hota sva u loke cikitvānityagnirvai hotā tasyaiṣa svo loko yatkṛṣṇājinaṃ cikitvāniti vidvānityetatsādayā yajñaṃ sukṛtasya yonāviti kṛṣṇājinaṃ vai kukṛtasya yonirdevāvīrdevānhaviṣā yajāsīti devaḥ sandevānavanhaviṣā yajāsītyetadagne bṛhadyajamāne vayo dhā iti yajamānāyāśiṣamāśāste

And these two following ones are Trishtubhs,--(Vâg. S. XI, 35, 36; Rik S. III, 29, 8; II, 9, 1). Now, the Trishtubh is the body (self): it is his (Agni's) body he makes up by means of these two (verses). 'Seat thee, O Hotri, in thine own place, thou, the mindful,'--the Hotri, doubtless, is Agni; and this, the black antelope skin, is indeed his own place; 'the mindful,' that is, 'the wise one;'--'establish the sacrifice in the seat of the good work!'--the seat of the good work doubtless is the black antelope skin;--'god-gladdening, thou shalt worship the gods with offering!'--that is, 'being a god, gratifying the gods, thou shalt worship (them) with offering;'--'Bestow, O Agni, great vigour upon the Sacrificer!'--thereby he implores a blessing upon the Sacrificer.