Bhashya
तथा यजुषाम् ।कथम् ? एष उ एव ब्रह्मणस्पतिः ।वाग्वै ब्रह्म-- ब्रह्म यजुः ; तच्च वाग्विषेष एव ।तस्यावाचो यजुषो ब्रह्मणः, एष पतिः ; तस्मादु ब्रह्मणस्पतिः--पूर्ववत् ॥कथं पुनरेतदवगम्यते बृहतीब्रह्मणोर्ऋग्यजुष्ट्वं न पुनरन्या-र्थत्वमिति ? उच्यते-- वाचः अन्ते सामसामानाधिकरण्य-निर्देशात् 'वाग्वै साम' इति ।तथा च 'वाग्वै बृहती''वाग्वै ब्रह्म' इति च वाक्समानाधिकरणयोर्ऋग्यजुष्ट्वं यु-क्तम् ।परिशेषाच्च-- साम्न्यभिहिते ऋग्यजुषी एव परि-शिष्टे ।वाग्विषेशत्वाच्च-- वाग्विषेशौ हि ऋग्यजुषी ; तस्मा-त्तयोर्वाचा समानाधिकरणता युक्ता ।अविशेषप्रसङ्गाच्च--'साम' 'उद्गीथः' इति च स्पष्टं विशेषाभिधानत्वम् , तथाबृहतीब्रह्मशब्दयोरपि विशेषाभिधानत्वं युक्तम् ; अन्यथा अ-निर्धारितविशेषयोरानर्थक्यापत्तेश्च, विशेषाभिधानस्य वाङ्गा-ङ्गत्वे चोभयत्र पौनरुक्त्यात् ; ऋग्यजुःसामोद्गीथशब्दानांच श्रुतिष्वेवं क्रमदर्शनात् ॥
In plain words
And similarly with the yajus mantras. How so? This very being is Brahmanaspati. Speech is indeed Brahman, the yajus, and it is nothing other than a specific form of speech. Of that speech, of the yajus, of Brahman, this is the lord; hence he is Brahmanaspati—just as explained before. How again is it understood that bṛhatī and brahman refer to the ṛk and yajus, and not to something else? It is answered: because at the conclusion of the section on speech there is co-reference with the sāman, as in the statement, 'Speech is indeed the sāman.' And likewise, statements like 'Speech is indeed the bṛhatī' and 'Speech is indeed Brahman' make it entirely appropriate that these terms, sharing the same case as speech, denote the ṛk and yajus. Furthermore, by the rule of remainder, once the sāman has been named, only the ṛk and yajus are left. Because they are modifications of speech, it is fitting that they share co-reference with speech. And to avoid the flaw of non-specification—just as 'sāman' and 'udgītha' clearly denote specific entities, so too must the words bṛhatī and brahman denote specific entities. Otherwise, failing to determine their specific meaning would render them meaningless, or if treated as mere limbs of speech, it would result in tedious repetition. Moreover, this corresponds to the established sequence in which the terms ṛk, yajus, sāman, and udgītha appear throughout the vedic texts.
Close to the Sanskrit
Likewise of the yajus texts. How? This indeed is Brahmanaspati. Speech verily is Brahman, the yajus; and that is a modification of speech indeed. Of that speech, of the yajus, of Brahman, this is the lord; therefore Brahmanaspati--as before. How again is this understood, that bṛhatī and brahman are yajus and ṛk, and not having another meaning? It is said: because of the instruction of co-reference with sāman at the end of speech, in 'speech verily is sāman'. And thus 'speech verily is bṛhatī', 'speech verily is Brahman', the state of being ṛk and yajus for those having co-reference with speech is proper. And from remainder, when sāman is stated, ṛk and yajus alone are remaining. And because of being a modification of speech, ṛk and yajus are indeed modifications of speech; therefore their co-reference with speech is proper. And because of the contingency of non-specification, as 'sāman', 'udgītha' are clearly expressions of particulars, similarly the expression of particulars for the words bṛhatī and brahman is also proper; otherwise due to the fault of meaninglessness for the two whose particular is undetermined, and in the state of being a limb of speech due to tautology in both places; and because of the observation of order thus for the words ṛk, yajus, sāman, and udgītha in the scriptures.