Bhashya
तं परलोकाय गच्छन्तमात्मानम्, विद्याकर्मणी- विद्या च कर्म च विद्याकर्मणी, विद्या सर्वप्रकारा विहिता प्रतिषिद्धा च अविहिता अप्रतिषिद्धा च, तथा कर्म विहितं प्रतिषिद्धं च अविहितमप्रतिषिद्धं च, समन्वारभेते सम्यगन्वारभेते अन्वालभेते अनुगच्छतः; पूर्वप्रज्ञा च- पूर्वानुभूतविषया प्रज्ञा पूर्वप्रज्ञा अतीतकर्मफला-नुभववासनेत्यर्थः ; सा च वासना अपूर्वकर्मारम्भे कर्मविपाके च अङ्गं भवति ; तेन असावपि अन्वारभते ; न हि तया वासनया विना कर्म कर्तुं फलं च उपभोक्तुं शक्यते ; न हि अनभ्यस्ते विषये कौशलम् इन्द्रियाणां भवति ; पूर्वानुभववासनाप्रवृत्तानां तु इन्द्रियाणाम् इह अभ्यासमन्तरेण कौशलमुपपद्यते ; दृश्यते च केषांचित् कासुचित्क्रियासु चित्रकर्मादिलक्षणासु विनैव इह अभ्यासेन जन्मत एव कौशलम्, कासुचित् अत्यन्तसौकर्ययुक्तास्वपि अकौशलं केषांचित् ; तथा विषयोपभोगेषु स्वभावत एव केषांचित् कौशलाकौशले दृश्येते ; तच्च एतत्सर्वं पूर्वप्रज्ञोद्भवानुद्भवनिमित्तम् ; तेन पूर्वप्रज्ञया विना कर्मणि वा फलोपभोगे वा न कस्यचित् प्रवृत्तिरुपपद्यते ।तस्मात् एतत् त्रयं शाकटिकसंभारस्थानीयं परलोकपथ्यदनं विद्याकर्मपूर्वप्रज्ञाख्यम् ।यस्मात् विद्याकर्मणी पूर्वप्रज्ञा च देहान्तरप्रतिपत्त्युपभोगसाधनम् , तस्मात् विद्याकर्मादि शुभमेव समाचरेत् , यथा इष्टदेहसंयोगोपभोगौ स्याताम्— इति प्रकरणार्थः ॥
In plain words
So this is what actually travels with the self on its way to the next world: knowledge and action, as a pair — every kind there is, whether commanded, forbidden, or simply neither. Both cling to the self and follow it, exactly as provisions follow a traveler. Alongside them travels a third thing: what we're calling 'prior cognition' — really just the accumulated residue of everything you've done and experienced before. That residue is what makes new action possible at all, and what lets its fruit ripen and be enjoyed; without it, nothing could be done and nothing could be tasted. You can see this everywhere: a skill nobody was taught still shows up in some people from birth, in painting and crafts like it, while others remain clumsy even at things that could hardly be easier. The same holds for pleasure itself — some people simply take to certain enjoyments naturally, others don't. None of that is random; it all comes down to whether this prior impression is present or not. Without it, no one — literally no one — could act or enjoy the fruit of acting. So these three things — knowledge, action, and prior impression — are exactly what plays the part of the cart-driver's provisions on the road to the next life. And because they are what actually secures and lets you enjoy your next body, the real takeaway is simple: act well now, and only well, so that when the time comes, you find yourself joined to the body you actually want, able to enjoy it fully.
Close to the Sanskrit
Him, the self going toward the other world — knowledge-and-action: knowledge and action [together are] 'knowledge-and-action.' Knowledge [is] of every kind: enjoined and prohibited, and unenjoined and unprohibited; likewise action [is] enjoined, prohibited, and unenjoined-unprohibited — [these] properly accompany [him], [that is] they follow closely, they attach themselves, they accompany. And prior cognition — [that is] cognition whose object was previously experienced, prior cognition, [that is] the impression of the experience of the fruit of past action, that is the meaning. And that impression becomes a contributing factor in the commencement of new action and in the ripening of action; therefore it too accompanies [him]. For without that impression it is not possible to perform action or to enjoy its fruit. For skill on the part of the senses does not occur in a matter that has not been practiced; but for senses impelled by the impression of prior experience, skill arises here even without practice. And it is seen that, in the case of some, in certain activities marked by painting and the like, skill [occurs] here from birth itself, without any practice at all; [while], in certain [activities] endowed with the greatest ease, unskillfulness [persists] in the case of some others. Likewise, in the enjoyment of objects, purely by [their own] nature, skill and unskillfulness are seen in the case of some. And all this has as its cause the arising or non-arising of prior cognition. Therefore, without prior cognition, no one's engagement is possible, whether in action or in the enjoyment of its fruit. Therefore, these three, standing in the place of the cart-driver's provisions — the food-for-the-road to the other world — are called 'knowledge-action-prior-cognition.' Since knowledge-and-action and prior cognition are the means of attaining and enjoying another body, therefore one should practice only what is auspicious in the way of knowledge, action and the rest, so that union with, and enjoyment of, a desired body may come about — this is the purport of the section.