Śatapatha Brāhmaṇa ("of a hundred paths") 13.5.2.21

13.5.2.21

athādhvaryuṃ yajamānaḥ pṛcati pṛcāmi tvā paramantam pṛthivyā iti tam pratyāheyam vediḥ paro antaḥ pṛthivyā iti

The Sacrificer then asks the Adhvaryu (Vâg. S. XXIII, 61), 'I ask thee about the farthest end of the earth, [I ask where is the navel of the world; I ask thee about the seed of the vigorous steed; I ask thee about the highest seat of speech];' and he replies (ib. 62), 'This altar-ground is the farthest end of the earth; [this sacrifice is the navel of the world; this Soma-juice is the seed of the vigorous steed; this Brahman (priest) is the highest seat of speech].'