This shloka completes the sentence that began in 15.3. In 15.3, Bhagavān said that the deeply rooted samsāra tree should be cut with the firm weapon of asaṅga, detachment. But the sentence did not end there. It said, “having cut…” and now 15.4 tells us what must be done after that. The seeker should not stop with detachment. Detachment is only the first preparation. After reducing dependence on the world, the seeker must turn toward the goal and pursue the remaining disciplines.

The first two and a half verses of the chapter described samsāra. Beginning from the second half of 15.3, the teaching moved to samsāra-nivṛtti-upāyaḥ, the means of freedom from samsāra. Four disciplines are highlighted in this section: vairāgyam, śaraṇāgati, sadguṇāḥ, and Vedānta-vicāraḥ. Vairāgyam was introduced in 15.3 through asaṅga-śastra. In 15.4, two more disciplines are brought out: Vedānta-vicāraḥ and śaraṇāgati. Sadguṇāḥ will be elaborated in the next verse.

The verse begins with tataḥ — thereafter. This does not mean “after some random event.” It means after the mind has been prepared. Just as a farmer sows seeds only after preparing the field, the seeker must enter Vedānta-vicāra after preparing the mind through the required qualifications. This is similar to the opening of the Brahma-sūtra: athāto brahma-jijñāsā — thereafter, enquiry into Brahman. “Thereafter” means after gaining the necessary inner preparedness.

The next phrase is tat padaṃ parimārgitavyam — that goal must be sought. Padam here means the ultimate destination, Brahman. The same Brahman that was earlier presented as the root and support of the samsāra tree is now presented as the destination of the seeker. The word padam is therefore very meaningful: it can mean the support or substratum, and it can also mean the destination. Brahman is both — the support of the world and the goal of the seeker.

Parimārgitavyam means it must be thoroughly sought or enquired into. This does not mean searching for Brahman as though it is an object hidden somewhere in the world. Brahman is not found by travelling to a distant place. Brahman is to be known through Vedānta-vicāra, systematic enquiry into the teaching of the scriptures. Self-enquiry requires the proper instrument, and that instrument is śāstra-pramāṇam, the Vedāntic scriptures. Just as one uses a mirror to see one’s own face, one uses the śāstra to understand oneself. Thus ātma-vicāra is not vague introspection; it is Vedānta-vicāra through śravaṇa, manana, and nididhyāsana.

This is the primary discipline because ignorance is the real problem. Vairāgyam, śaraṇāgati, and sadguṇāḥ prepare the mind, but Vedānta-vicāra alone removes ignorance. A surgery requires proper conditions — sugar level, pressure, instruments, and preparation — but the surgery itself removes the disease. Similarly, supporting disciplines prepare the mind, but Vedānta-vicāra removes self-ignorance.

Then Bhagavān says: yasmin gatā na nivartanti bhūyaḥ — having reached which, they do not return again. This means that Brahman is not a temporary destination like svarga or a better birth. Any result produced by karma is temporary. Heaven can be reached and exhausted. A higher body can be gained and lost. But Brahman is not a karmic result; it is the recognition of the truth. When ignorance is removed, the freedom gained is not lost again.

The second half of the verse gives the discipline of śaraṇāgati: tam eva ca ādyam puruṣaṃ prapadye — I surrender to that very primal Puruṣa. Prapadye means “I surrender.” This surrender is to Bhagavān in any iṣṭa-devatā form. Human effort is necessary, but effort alone is not enough. Any undertaking succeeds only when two factors are present: prayatna, sincere effort, and Īśvara-anugraha, Bhagavān’s grace. Therefore the seeker surrenders to Bhagavān and prays for the grace required to pursue the mokṣa-mārga.

Bhagavān is called ādyaṃ puruṣam — the original Puruṣa. Ādya means original, the source from which everything emerges. Puruṣa here is the all-pervading Bhagavān, the indwelling reality. The verse describes that Puruṣa as yataḥ pravṛttiḥ prasṛtā purāṇī — from whom the ancient movement of creation has proceeded. Creation beginning from space itself emerges from that source. The creation is purāṇī, ancient, beginningless from our standpoint; it is not something whose first moment can be located. The seeker surrenders to that original source.

So 15.4 gives two crucial steps after vairāgyam. First, seek Brahman through systematic Vedānta-vicāra. Second, surrender to Bhagavān, the original source of creation, for grace on the path. The goal is not a higher branch of the samsāra tree, but Brahman itself — the padam from which there is no return.