Bhashya
देवा ह वै प्रजापतिमनुवन्नित्यादि स होवाच प्रजापतिरित्य-न्तं स्पष्टार्थम् ।अत्र हि सर्वे मन्त्राः प्रणवादिकाः तदादिन्या-येन प्रणवं मूलमन्त्राक्षरं पुनः प्रणवं सर्वेषु मन्त्रेषु दर्शयति ।अत्र हि मन्त्रेषु यच्छब्दद्वयेन अन्यतः सिद्धमनूद्य कुत्रचिच्छ-
In plain words
This much needs no unpacking: the gods asked, and Prajāpati answered — that whole opening is plain on its face. What is worth noticing is subtler. Every mantra here opens on Om, and the commentary points out why: once a text leads with something, that opening governs everything that follows — so Om, the root syllable beneath every mantra, keeps resurfacing throughout them. And twice in these mantras a small word, 'which', does real work: it reaches back to something already settled elsewhere and pulls it into this new sentence, rather than asserting something fresh.
Close to the Sanskrit
The gods indeed questioned Prajāpati — 'and so on' — up to 'Prajāpati then said' — this much is clear in meaning. Here indeed, by the maxim that the opening term sets the pattern, all the mantras beginning with Om show the syllable Om — the root syllable of the mantra — again in all the mantras. Here indeed, in the mantras, by the pair of the word 'yat', having restated what is established elsewhere, in some instance [the force of the word...]