अथ यदु चैवास्मिञ्छव्यं कुर्वन्ति यदि च नार्चिषमेवाभिसंभवन्त्यर्चिषोऽहरह्न आपूर्यमाणपक्षमापूर्यमाणपक्षाद्यान्षडुदङ्ङेति मासांस्तान्मासेभ्यः संवत्सरं संवत्सरादादित्यमादित्याच्चन्द्रमसं चन्द्रमसो विद्युतं तत् पुरुषोऽमानवः स एनान्ब्रह्म गमयत्येष देवपथो ब्रह्मपथ एतेन प्रतिपद्यमाना इमं मानवमावर्तं नावर्तन्ते नावर्तन्ते ॥ ४.१५.५ ॥
In plain words
Now whether men perform the funeral rites for such a one or not, they go on to the flame, from the flame to the day, from the day to the bright fortnight, from the bright fortnight to the six months in which the sun moves north, from those months to the year, from the year to the sun, from the sun to the moon, from the moon to lightning. There is a person who is not human; he leads them on to Brahman. This is the path of the gods, the path of Brahman. Those who go by it do not return to this human round — do not return.
The commentators
Chāndogyopaniṣadbhāṣyam
अथेदानीं यथोक्तब्रह्मविदः गतिरुच्यते ।
यत् यदि उ च एव अस्मिन् एवंविदि शव्यं शवकर्म मृते कुर्वन्ति, यदि च न कुर्वन्ति ऋत्विजः, सर्वथाप्येवंवित् तेन शवकर्मणा अकृतेनापि प्रतिबद्धो न ब्रह्म न प्राप्नोति ; न च कृतेन शवकर्मणा अस्य कश्चनाभ्यधिको लोकः, ‘न कर्मणा वर्धते नो कनीयान्’ इति श्रुत्यन्तरात् । शवकर्मण्यनादरं दर्शयन् विद्यां स्तौति, न पुनः शवकर्म एवंविदः न कर्तव्यमिति । अक्रियमाणे हि शवकर्मणि कर्मणां फलारम्भे प्रतिबन्धः कश्चिदनुमीयतेऽन्यत्र । यत इह विद्याफलारम्भकाले शवकर्म स्याद्वा न वेति विद्यावतः अप्रतिबन्धेन फलारम्भं दर्शयति । ये सुखाकाशमक्षिस्थं संयद्वामो वामनीर्भामनीरित्युेवंगुणमुपासते प्राणसहितामग्निविद्यां च, तेषामन्यत्कर्म भवतु मा वा भूत् सर्वथा अपि ते अर्चिषमेवाभिसंभवन्ति अर्चिरभिमानिनीं देवतामभिसंभवन्ति प्रतिपद्यन्त इत्यर्थः । अर्चिषः अर्चिर्देवताया अहः अहरभिमानिनीं देवताम्, अहः आपूर्यमाणपक्षं शुक्लपक्षदेवताम्, आपूर्यमाणपक्षात् यान्षण्मासान् उदङ् उत्तरां दिशम् एति सविता तान्मासान् उत्तरायणदेवताम्, तेभ्यो मासेभ्यः संवत्सरं संवत्सरदेवताम्, ततः संवत्सरादादित्यम्, आदित्याच्चन्द्रमसम्, चन्द्रमसो विद्युतम् । तत् तत्रस्थान् तान् पुरुषः कश्चिद्व्रह्मलोकादेत्य अमानवः मानव्यां सृष्टौ भवः मानवः न मानवः अमानवः स पुरुषः एनान्ब्रह्म सत्यलोकस्थं गमयति गन्तृगन्तव्यगमयितृत्वव्यपदेशेभ्यः, सन्मात्रब्रह्मप्राप्तौ तदनुपपत्तेः । 'ब्रह्मैव सन्ब्रह्माप्येति' इति हि तत्र वक्तुं न्याय्यम् । सर्वभेदनिरासेन सन्मात्रप्रतिपत्तिं वक्ष्यति । न च अदृष्टो मार्गोऽगमनायोपतिष्ठते, 'स एनमविदितो न भुनक्ति' इति श्रुत्यन्तरात् । एष देवपथः देवैरर्चिरादिभिर्गमयितृत्वेनाधिकृतैरुपलक्षितः पन्था देवपथ उच्यते । ब्रह्म गन्तव्यं तेन च उपलक्षित इति ब्रह्मपथः । एतेन प्रतिपद्यमाना गच्छन्तो ब्रह्म इमं मानवं मनुसंबन्धिनं मनोः सृष्टिलक्षणमावर्तं नावर्तन्ते आवर्तन्तेऽस्मिञ्जननमरणप्रबन्धचक्रारूढा घटीयन्त्रवत्पुनः पुनरित्यावर्तः तं न प्रतिपद्यन्ते । नावर्तन्ते इति द्विरुक्तिः सफलाया विद्यायाः परिसमाप्तिप्रदर्शनार्था ॥
In plain words
Now is explained the journey of the one who knows Brahman as previously described.
Whether funeral rites are performed for a person of true knowledge upon death or left undone by the priests, such a knower is never hindered by the omission of rites from attaining brahman; nor do rites add any special world to his attainment, as another text confirms: 'It does not grow larger through work, nor smaller.' By showing disregard for funeral rites, the text praises the supreme power of knowledge, rather than prohibiting rites for the wise. Since the non-performance of rites implies a possible obstruction to ordinary results elsewhere, the text demonstrates that for the wise person, the fruit of knowledge unfolds unobstructed, regardless of whether funeral rites take place. Those who meditate on the blissful space within the eye under the names of 'attractor of desires,' 'leader of desires,' and 'radiant,' alongside the vital breath and fire meditation—whether or not they perform any other actions, they reach the path of light, attaining the deity presiding over the flame. From the flame they pass to the day, from the day to the bright fortnight, and thence to the six months of the sun's northern course, followed by the northern path deity, the year, the sun, the moon, and lightning. At that stage, a non-human guide coming from brahmaloka leads these travelers to the brahman of satyaloka—a guidance necessary because scripture speaks of goers, destinations, and guides, which only makes sense when attaining a conditioned realm, unlike pure, non-dual brahman, regarding which scripture says, 'Being brahman, he attains brahman.' The text will presently set forth the realization of pure existence through the elimination of all distinctions. Nor is an unknown path ever conjured out of nothing, for another text warns, 'Unrecognized, it does not protect.' This path, marked out by guiding deities like flame, is known as the path of the gods, and because it leads to brahman, it is also the path of brahman. Traveling along this path toward brahman, they never return to the whirlpool of human existence sprung from Manu—that endless turning on the wheel of birth and death like a water-wheel—they never return to it. The repetition of 'they do not return' serves to show that the teaching of liberating knowledge has reached its complete fulfillment.
Close to the Sanskrit
Now henceforth the journey of the knower of Brahman as described is stated.
If indeed or even in this knower funeral rites are performed when dead, or if priests do not perform them, in every way the knower of this is not obstructed by that funeral action so as not to attain brahman; nor is any additional world his through performed funeral action, 'neither increases by action nor grows less' from another śruti. Showing disregard in funeral action, he praises knowledge, not that funeral action is not to be done by the knower. For when funeral action is undone, some obstruction to the results of actions is inferred elsewhere. Since here at the time of the commencement of the fruit of knowledge, funeral action may or may not be, he shows the commencement of fruit for the knower without obstruction. Those who meditate on the blissful space situated in the eye, as attractor of desires, leader of desires, and shining forth, along with the prana and fire meditation—let their other action be or not be, in every way they attain flame indeed, they attain the flame-presiding deity. From flame, the day-presiding deity, from day the waxing fortnight deity, from the waxing fortnight the six months which the sun goes in the northern direction—those months the northern path deity; from those months the year deity; then from the year the sun, from the sun the moon, from the moon lightning. There, a certain non-human person coming from brahmaloka—born in human creation, human, not human, non-human—that person leads these to brahman situated in satyaloka, from designations of goer, destination, and guidingness, upon attainment of pure existence brahman, since that is impossible with respect to attaining pure existence brahman. 'Being brahman indeed, he attains brahman'—thus it is proper to speak there. He will speak of the realization of pure existence by the elimination of all differences. Nor does an unseen path present itself for non-going, 'unknown, it does not protect him' from another śruti. This path of the gods, characterized by the guiding deities beginning with flame, is called the path of the gods. And because it is characterized by brahman as the destination, it is the path of brahman. Proceeding by this, going to brahman, they do not return to this human whirlpool connected with Manu's creation—they return, caught in the wheel of birth and death like a water-wheel, again and again, thus it is a whirlpool—that they do not reach. 'They do not return'—this duplication is for the purpose of showing the completion of fruitful knowledge.