yuñjann evaḿ sadātmānaḿ
yogī niyata-mānasaḥ
śāntiḿ nirvāṇa-paramāḿ
mat-saḿsthām adhigacchati

Translation of Bhagavad Gita 6.15

Thus practicing constant control of the body, mind and activities, the mystic transcendentalist, his mind regulated, attains to the kingdom of God [or the abode of Krishna] by cessation of material existence.

Commentary by Sri A.C. Bhaktivedanta Swami Prabhupada of Gaudiya Sampradaya:

The ultimate goal in practicing yoga is now clearly explained. Yoga practice is not meant for attaining any kind of material facility; it is to enable the cessation of all material existence. One who seeks an improvement in health or aspires after material perfection is no yogi according to Bhagavad-gita. Nor does cessation of material existence entail one’s entering into “the void,” which is only a myth. There is no void anywhere within the creation of the Lord. Rather, the cessation of material existence enables one to enter into the spiritual sky, the abode of the Lord. The abode of the Lord is also clearly described in the Bhagavad-gita as that place where there is no need of sun, moon or electricity. All the planets in the spiritual kingdom are self-illuminated like the sun in the material sky. The kingdom of God is everywhere, but the spiritual sky and the planets thereof are called param dhama, or superior abodes.

A consummate yogi, who is perfect in understanding Lord Krishna, as is clearly stated herein by the Lord Himself (mat-cittah, mat-parah, mat-sthanam), can attain real peace and can ultimately reach His supreme abode, Krishnaloka, known as Goloka Vrindavana. In the Brahma-samhita (5.37) it is clearly stated, goloka eva nivasaty akhilatma-bhutah: the Lord, although residing always in His abode called Goloka, is the all-pervading Brahman and the localized Paramatma as well by dint of His superior spiritual energies. No one can reach the spiritual sky (Vaikuntha) or enter into the Lord’s eternal abode (Goloka Vrindavana) without the proper understanding of Krishna and His plenary expansion Vishnu. Therefore a person working in Krishna consciousness is the perfect yogi, because his mind is always absorbed in Krishna’s activities (sa vai manah krishna-padaravindayoh). In the Vedas also (Shvetasvatara Upanishad 3.8) we learn, tam eva viditvati mrityum eti: “One can overcome the path of birth and death only by understanding the Supreme Personality of Godhead, Krishna.” In other words, perfection of the yoga system is the attainment of freedom from material existence and not some magical jugglery or gymnastic feats to befool innocent people.

Commentary by Sri Vishvanatha Chakravarthi Thakur of Gaudiya Sampradaya:

Continually engaging the mind (atmanam yunjan) in dhyana yoga because the consciousness is devoid of sense objects (niyata manasah), he then attains the dissolution of samsara (santim), in which supreme liberation (nirvana) can be attained, and in which there is continuous existence in My aspect as the impersonal brahman (mat samstham).

Commentary by Sri Ramanuja of Sri Sampradaya:

6.15 ‘Ever applying his mind on Me,’ i.e., the Supreme Brahman, the Supreme Person and the holy and auspicious object of meditation, ‘the Yogin of controlled mind,’ i.e., one having his mind steady because of his being purified in mind through contact with Me, comes to the peace which abides in Me, which is of the highest degree of beatitude. That means he comes to the peace which is the supreme end of beatitude which abides in Me. For the person who commences Yoga of the self, Sri Krsna, after thus teaching how the mind should be fixed on the Lord, who is the holy and auspicious object of meditation, proceeds in order to effect the purification of the mind, to speak of the other side of Yoga:

Commentary by Sri Sridhara Swami of Rudra Sampradaya:

Lord Krishna states the results of concentrated meditation is the cessation of worldly existence and promotion to the effulgent eternal realms where one abides beyond the Brahman or the spiritual substratum pervading all existence.

Commentary by Sri Madhvacharya of Brahma Sampradaya:

Lord Krishna uses the compound word nirvana-paramam meaning the supreme bliss which commences for an embodied being after the cessation of birth and death in the physical body in the material existence and the attainment of the eternal spiritual nature.

Commentary by Sri Keshava Kashmiri of Kumara Sampradaya:

Lord Krishna speaks of the results one reaps meditating on the Supreme Lord by practising yoga or the science of the individual consciousness attaining communion with the ultimate consciousness. The result is one achieves moksa or liberation from the material existence.

Commentary by Sri Adi Shankaracharya of Advaita Sampradaya:

6.15 Yunjan, concentrating; atmanam, the mind; evam, thus, according to the methods shown above; sada, for ever; the yogi, niyata-manasah, of controlled mind; adhi-gacchati, achieves; santim, the Peace, the indifference to worldly attachments and possessions; nirvana-paramam, which culminates in Liberation; and mat-samstham, which abides in Me. Now are bieng mentioned the rules about the yogi’s food etc.:

Commentary by Sri Abhinavagupta of Kaula Tantra Sampradaya:

6.10-15 Yogi etc. upto adhigacchati. Self : the mind. Let him yoke it : let him make it single-pointed. Always : not for a limited period of time. If the conditions like remaining alone etc., are fulfilled, this [controlling of mind] is possible and not otherwise. On account of the firmness of seat, the time-nerve (or the body ?) remains firm and due to this, mind remains firm. He, by whom the mental activities i.e., those that are in the form of intention, and other activities of the sense-organs are subdued i.e., are brought under full control; [he is the person of the subdued mental and sensual activities]. Holding : i.e., with effort. If the nose-tip is looked at, [it is possible] not to look at [different] directions. Let him remain endowed with the state of having Me alone as supreme goal. This is the meaning [here]. He who yokes i.e., concentrates his self (mind) in this manner, there arises for him Peace in which the culmination – as far as the end-is the same as attaining Me.

Sanskrit Shloka Without Transliteration Marks:

yuñjann evam sadatmanam
yogi niyata-manasah
santim nirvana-paramam
mat-samstham adhigacchati

Sanskrit to English Word for Word Meanings:

yuñjan — practicing; evam — as mentioned above; sadā — constantly; ātmānam — body, mind and soul; yogī — the mystic transcendentalist; niyata-mānasaḥ — with a regulated mind; śāntim — peace; nirvāṇa-paramām — cessation of material existence; mat-saḿsthām — the spiritual sky (the kingdom of God); adhigacchati — does attain.