Bhashya
यस्मात् सर्वैषणाविनिवृत्तः स एष नेति नेत्यात्मानमात्मत्वेनोपगम्य तद्रूपेणैव वर्तते, तस्मात् एतम् एवंविदं नेति नेत्यात्मभूतम्, उ ह एव एते वक्ष्यमाणे न तरतः न प्राप्नुतः—इति युक्तमेवेति वाक्यशेषः ।के ते इत्युच्यते—अतः अस्मान्निमित्तात् शरीरधारणादिहेतोः, पापम् अपुण्यं कर्म अकरवं कृतवानस्मि—कष्टं खलु मम वृत्तम्, अनेन पापेन कर्मणा अहं नरकं प्रतिपत्स्ये—इति योऽयं पश्चात् पापं कर्म कृतवतः—परितापः स एनं नेति नेत्यात्मभूतं नतरति ; तथा अतः कल्याणं फलविषयकामाग्निमित्तात् यज्ञदानादिलक्षणं पुण्यं शोभनं कर्म कृतवानस्मि, अतोऽहम् अस्य फलं सुखमुपभोक्ष्ये देहान्तरे— इत्येषोऽपि हर्षः तं न तरति ।उभे उ ह एव एषः ब्रह्मवित् एते कर्मणी तरति पुण्यपापलक्षणे ।एवं ब्रह्मविदः संन्यासिन उभे अपि कर्मणी क्षीयेते— पूर्वजन्मनि कृते ये ते, इह जन्मनि कृते ये ते च ; अपूर्वे च न आरभ्येते ।किं च नैनं कृताकृते, कृतं नित्यानुष्ठानम्, अकृतं तस्यैव अक्रिया, ते अपि कृताकृते एनं न तपातः ; अनात्मज्ञं हि, कृतं फलदानेन, अकृतं प्रत्यवायोत्पादनेन, तपातः ; अयं तु ब्रह्मवित् आत्मविद्याग्निना सर्वाणि कर्माणि भस्मीकरोति, ‘यथैधांसि समिद्धोऽग्निः’ इत्यादिस्मृतेः ; शरीरारम्भकयोस्तु उपभोगेनैव क्षयः ।अतो ब्रह्मवित् अकर्मसम्बन्धी ॥
In plain words
Someone who has let go of every craving, who has met this Self — the one named only by 'not this, not this' — as his very own Self, now simply lives as that. So when it is said that these two things to come do not touch him, do not reach him, it fits perfectly — the rest of the sentence explains which two. What are they? Here is the voice of ordinary remorse: 'Because I had to keep this body going, I did something wrong — how wretched, what I've done — and now this sin will drag me down to ruin.' That guilt, the ache that follows a bad act, cannot touch the one who has become 'not this, not this'. And here is the voice of ordinary pride: 'Because I wanted a reward, I did something good — sacrifices, gifts — and now I'll enjoy the sweetness of it in another life.' That pleasure, too, cannot touch him. This knower of Brahman moves past both, merit and demerit alike. Both kinds of action wear away for the renunciant who knows this: whatever he did in an earlier life, whatever he has done in this one — and nothing new begins. Nor do the done and the undone burn him: the done is simply the routine you keep up, the undone is simply not keeping it up — neither has any grip on him. They only burn someone who doesn't know the Self — reward for the done, guilt for the undone. But this knower burns every action to ash in the fire of knowing the Self, exactly as the old teaching says: a blazing fire turns fuel to ash. Only the two actions that started this very body still have to run their course, and they wear off simply by being lived through. So the one who knows Brahman has, in the end, nothing left to do with action at all.
Close to the Sanskrit
Since he who has turned away from all desire, having approached this Self characterized as 'not this, not this' in the capacity of his own Self, abides only in that very form — therefore, concerning this one who knows thus, who has become that Self known as 'not this, not this', these two things about to be stated do not overcome him, do not reach him: this is indeed a fitting reading; such is the remainder of the sentence. Which two are they? It is explained: 'Because of this — for reasons such as the maintenance of the body — I have done a sinful, unmeritorious deed; wretched indeed is my conduct; by this sinful act I shall fall into hell' — this remorse, arising afterward in one who has done a sinful deed, does not overcome him who has become that Self known as 'not this, not this'. Likewise: 'Because of this fire of desire for a fruit, I have done a good, meritorious deed marked by sacrifice, gift-giving, and so on; therefore I shall enjoy its pleasant fruit in another body' — this joy, too, does not overcome him. This knower of Brahman indeed overcomes both these actions, characterized as merit and demerit. Thus, for the renunciant knower of Brahman, both actions perish — those done in a former birth and those done in this birth — and new ones are not begun. Moreover, neither the done nor the undone torment him: the 'done' is the constant observance, the 'undone' is simply its non-performance; these too do not torment him. They do torment one who does not know the Self — the 'done' by giving its fruit, the 'undone' by producing a lapse. But this knower of Brahman reduces all actions to ashes by the fire of Self-knowledge, as in the smṛti beginning 'as a blazing fire consumes fuel'. For the two actions that initiate a body, however, exhaustion comes only through experience. Therefore the knower of Brahman has no connection with action at all.