Bhashya
तदेतद्वस्तु ब्राह्मणेनोक्तम् ऋचा मन्त्रेण अभ्युक्तम् प्रका-शितम् ।एषः नेति नेत्यादिलक्षणः नित्यो महिमा ; अन्ये तुमहिमानः कर्मकृता इत्यनित्याः ; अयं तु तद्विलक्षणो महिमास्वाभाविकत्वान्नित्यः ब्रह्मविदः ब्राह्मणस्य त्यक्तसर्वैषणस्य ।कुतोऽस्य नित्यत्वमिति हेतुमाह — कर्मणा न वर्धते शुभलक्ष-णेन कृतेन वृद्धिलक्षणां विक्रियां न प्राप्नोति ; अशुभेन कर्मणानो कनीयान् नाप्यपक्षयलक्षणां विक्रियां प्राप्नोति ; उपचयाप-चयहेतुभूता एव हि सर्वा विक्रिया इति एताभ्यां प्रतिषिध्य-न्ते ; अतः अविक्रियत्वात् नित्य एष महिमा ।तस्मात् तस्यैवमहिम्नः, स्यात् भवेत्, पदवित् — पदस्य वेत्ता, पद्यते गम्यतेज्ञायत इति महिम्नः स्वरूपमेव पदम् , तस्य पदस्य वेदिता ।किं तत्पदवेदनेन स्यादित्युच्यते — तं विदित्वा महिमानम् ,न लिप्यते न संबध्यते कर्मणा पापकेन धर्माधर्मलक्षणेन,उभयमपि पापकमेव विदुषः ।यस्मादेवम् अकर्मसंबन्धीएष ब्राह्मणस्य महिमा नेति नेत्यादिलक्षणः, तस्मात् एवं-वित् शान्तः बाह्येन्द्रियव्यापारत उपशान्तः, तथा दान्तःअन्तःकरणतृष्णातो निवृत्तः, उपरत: सर्वैषणाविनिर्मुक्तःसंन्यासी, तितिक्षुः द्वंद्वसहिष्णुः, समाहितः इन्द्रियान्तःक-रणचलनरूपाद्व्यावृत्त्या ऐकाग्र्यरूपेण समाहितो भूत्वा; तदे-तदुक्तं पुरस्तात् 'बाल्यं च पाण्डित्यं च निर्विद्य' इति ; आ-त्मन्येव स्वे कार्यकारणसंघाते आत्मानं प्रत्यक्चेतयितारं पश्य-ति ।तत्र किं तावन्मात्रं परिच्छिन्नम् ? नेत्युच्यते-सर्वं सम-स्तम् आत्मानमेव पश्यति, नान्यत् आत्मव्यतिरिक्तं वालमात्र-मात्रमप्यस्तीत्येवं पश्यति ; मननात् मुनिर्भवति जाग्रत्स्वप्नसुषु-प्ताख्यं स्थानत्रयं हित्वा ।एवं पश्यन्तं ब्राह्मणं नैनं पाप्मा पु-ण्यपापलक्षणः तरति, न प्राप्नोति ; अयं तु ब्रह्मवित् सर्वं पा-प्मानं तरति आत्मभावेनैव व्याप्नोति अतिक्रामति ।नैनं पा-प्मा कृताकृतलक्षणः तपति इष्टफलप्रत्यवायोत्पादनाभ्याम् ;सर्वं पाप्मानम् अयं तपति ब्रह्मवित् सर्वात्मदर्शनवह्निना भस्मी-करोति ।स एष एवंवित् विपापः विगतधर्माधर्मः, विरजःविगतरजः, रजः कामः, विगतकामः, अविचिकित्सः छिन्न-संशयः, अहमस्मि सर्वात्मा परं ब्रह्मेति निश्चितमतिः ब्राह्मणोभवति- अयं तु एवंभूतः एतस्यामवस्थायां मुख्यो ब्राह्म-णः, प्रागेतस्मात् ब्रह्मस्वरूपावस्थानात् गौणमस्य ब्राह्मण्यम् ।
In plain words
This is the same thing the prose just told you, and now the verse says it again, bringing it fully into the light. This glory — the one named only by 'not this, not this' — never runs out. Other kinds of greatness are built by action, and whatever is built that way eventually wears down. This one is different: it belongs to your own nature, so nothing can add to it and nothing can take from it — it is simply there, in the one who has let go of every desire and knows Brahman. Why does it never change? Because change always means either gaining or losing, and this glory does neither: a good deed cannot swell it, a bad deed cannot shrink it. Free of both, it simply cannot change — which is exactly why it lasts. So to know this glory is to know its true ground, its own 'station' — it is nothing apart from its own nature, reached, arrived at, known as itself. And what comes from knowing it? Simply this: no action, good or bad, can touch you anymore — because, seen from that height, good and bad turn out to be the same kind of burden. And because this glory has nothing to do with action at all, the one who knows it becomes quiet — the noise of the senses dies down; mastered — the mind stops craving; withdrawn — every desire let go; able to bear anything — heat, cold, praise, blame, all of it; gathered into one steady point — the restlessness of mind and senses settled into stillness. This is the same thing said earlier: having outgrown both childishness and cleverness. He looks into this very body and mind and sees, right there, the Self looking back — the one who is always the seer, never the seen. And does his seeing stop there? No — he sees the entire world as nothing but that Self; not even a hair's width of anything separate from it exists for him. Through this reflection he becomes a sage, done with waking, dreaming, and dreamless sleep alike. No wrong can touch a brāhmaṇa who sees this way, none can even come near him; he moves clean through every wrong there is, simply by being what he is. Neither what he has done nor what he has left undone can burn him, though both burn anyone who does not know this — one through reward, the other through guilt. He turns every wrong to ash in the fire of seeing everything as the Self. Cleared of merit and demerit both, cleared of restless craving, cleared of every doubt — certain now, simply, that 'I am the Self of everything, I am the highest Brahman' — this is what makes him a true brāhmaṇa. Before this, whatever he was called was only a name. Now, having settled into what he actually is, the name finally means what it says.
Close to the Sanskrit
This same matter has been stated by the brāhmaṇa-text, and declared, illumined, by the Ṛc verse. This eternal glory is characterized as 'not this, not this' and so on. Other glories, however, produced by action, are non-eternal; but this glory, distinct from those, is eternal because it is inherent by nature — it belongs to the brāhmaṇa who is a knower of Brahman, who has abandoned all desire. Why is this eternal? The reason is given: it does not increase by a good deed performed, undergoing the modification called increase; nor does it become less by an evil deed, undergoing the modification called decrease; for all modification consists precisely of increase or decrease, and by these two statements modification is negated of it; therefore, because it is free from modification, this glory is eternal. Therefore, one would be the knower of that very glory — the knower of its station: that which is reached, gone to, known, is the very own-form of the glory itself, called its 'station'; the knower of that station. What would result from knowing that station? It is explained: having known that glory, one is not tainted, not bound, by action, by evil, characterized as merit and demerit — for both alike are indeed evil for the knower. Since, then, this glory of the brāhmaṇa, characterized as 'not this, not this' and so on, has no connection with action, therefore one who knows thus is tranquil — quieted from the operation of the external senses; likewise subdued — turned away from the mind's craving; withdrawn — a renunciant fully freed from every desire; forbearing — tolerant of the pairs of opposites; composed — settled in one-pointedness by turning away from the wavering nature of the senses and the mind, having become so. This same point was stated earlier: 'having renounced both childishness and scholarship.' He sees, in his own self alone, within the aggregate of effect and cause, the Self as the inward-facing witness. Is this seeing limited to just that much? No — it is explained: he sees the entire, whole world as the Self alone; he sees that nothing else, not even the measure of a hair, exists apart from the Self. By reflection he becomes a sage, having abandoned the three states called waking, dream, and deep sleep. Evil, characterized as merit and demerit, does not overcome such a brāhmaṇa who sees thus, does not even reach him; but this knower of Brahman overcomes all evil — he pervades and transcends it by his very being as the Self. Evil, characterized as the done and the undone, does not burn him, through the production of the desired fruit and of transgression; this knower of Brahman burns all evil — he reduces it to ash by the fire of the vision of all as the Self. This one who knows thus becomes free from evil — merit and demerit gone; free from passion — passion being desire, [now] gone; free from doubt — doubt cut off, with the settled conviction 'I am the all-Self, the supreme Brahman'; he becomes a brāhmaṇa. But this one who has become such is, in this state, a brāhmaṇa in the primary sense; before this abiding in the very nature of Brahman, his brāhmaṇa-hood was only figurative.