Shatapatha Brahmana 11.5.9.10

11.5.9.10

kakubhaṃ rūpaṃ vṛṣabhasya rocate bṛhaditi etadvai kakubhaṃ rūpaṃ vṛṣabhasya rocate bṛhadya eṣa tapati śukraḥ śukrasya purogāḥ somaḥ somasya purogā iti tacukramevaitacukrasya purogāṃ karoti somaṃ somasya purogāṃ yatte somādābhyaṃ nāma jāgṛvi tasmai tvā gṛhṇāmītyetaddha vā asyādābhyaṃ nāma jāgṛvi yadvāktadvācamevaitadvāce gṛhṇāti

[Vâg. S. VIII, 41], 'Mightily shineth the towering form of the ball,'--for mightily indeed shines that towering form of the ball, to wit, yonder burning (sun);--'the bright one, the leader of the bright one, Soma, the leader of Soma,'--he thereby makes that bright (sun) the leader of the bright (Soma), and Soma the leader of the Soma;--'what indestructible, watchful name there is of thine, for that do I take thee;'--for this, to wit, speech, is indeed his (Soma's) indestructible (adâbhya), watchful name: it is thus speech he thereby takes for speech.