The Blessed Lord said: One who performs obligatory works without expecting their fruits — is a Sanyāsin and Yogi, and not one who does not maintain sacred fires and performs no (prescribed) actions.

That which is called Sannyāsa (Renunciation) O Arjuna, know to be Yoga (Karma Yoga). For no one becomes a true Karma Yogin without relinquishing the delusive identification of the body with the Self.

For the sage who seeks to ascend to the heights of Yoga, the action is said to be the means; but when one has reached the summit of Yoga, quiescence is said to be the means. or For one who is a neophyte (beginner) in yoga, the action is said to be the means; but when one has reached the summit of Yoga, quiescence (cessation or renunciation) is said to be the means.

When one loses all attachment for the sense-objects and to works, then one indeed has abandoned all desires and is considered to have reached the heights of Yoga.

One should elevate himself by his own mind and not allow himself to degrade, for the mind alone is the friend of the Self, and the mind alone is enemy as well. For him who has conquered the mind, the mind is the best of friends, but for one whose mind is uncontrolled; his very mind will be the greatest enemy.

For one who has conquered the mind, the Supersoul(Parmatma) is already reached, for he has attained tranquility. To such a man happiness and distress, heat and cold, honor and dishonor are all the same.

A person is said to be established in self-realization and is called a yogī [or mystic] when he is fully satisfied by virtue of acquired knowledge(jnana) and supra-sensory experience or science(vijnana). Such a person is situated in transcendence and is self-controlled. He sees everything-whether it be pebbles, stones or gold-as the same.

One who regards with equality, well-wishers, friends, foes, the indifferent, neutrals, the hateful, relatives, and even the righteous and the unrighteous — is special among yogis.

A Yogi looking forward to excelling in Yoga should practice constantly placing himself in a secluded (quiet) place and carefully concentrating his mind on his inner self leaving aside all physical desires and possessions

In a clean place, having established for oneself a firm seat which is neither too high nor too low, and covering it with cloth, deer-skin and kusha grass one over the other, there, sitting on the seat, focusing the mind in concentration, with the thoughts and the senses restrained, one should practice Yoga for the purification of the self.

Holding the trunk, head, and neck erect, motionless and steady, focusing [the attention] at the tip of the nose, and without looking around; Serene and fearless, firm in the vow of celibacy(Brahmacharya), holding the mind in check and fixing the thoughts on Me, one should sit in meditation, holding Me to be Supreme.

Thus practicing control of the body, mind, and activities (Practicing yoga) this way, the Yogi, attains the ultimate peace [in this life] and reaches my kingdom [after cessation of this body] abiding in me forever.

O Arjuna! Yoga is not accomplished by him who either eats too much or eats too little; nor by him who sleeps too much or does not sleep enough. Yoga, which ends all miseries, is accomplished only by those who has regulated his diet, formal in performing actions and regulated in sleeping and wakefulness.

When the yogī, by the practice of yoga, disciplines his mental activities and becomes situated in Transcendence-devoid of all material desires-he is said to have attained yoga.

As a lamp in a windless place does not waver, so the transcendentalist, whose mind is controlled, remains always steady in his meditation on the transcendent Self.

The stage of perfection is called trance, or samādhi, when one's mind is completely restrained from material mental activities by practice of yoga. This is characterized by one's ability to see the self by the pure mind and to relish and rejoice in the self. In that joyous state, one is situated in boundless transcendental happiness and enjoys himself through transcendental senses. Established thus, one never departs from the truth, and upon gaining this he thinks there is no greater gain. Being situated in such a position, one is never shaken, even in the midst of greatest difficulty. This indeed is actual freedom from all miseries arising from material contact.

This Yoga must be practiced with determination and with a mind free from despondency, renouncing without reserve, all desires born of imagination (sankalpa) and completely restraining the whole group of senses by the mind from all directions;

Gradually, step by step, with the mind firmly fixed, he should gradually attain tranquility(Samadhi, the deep meditation), Therefore fixing the mind in the self alone, he should not think of anything else.

Wherever the fickle and unsteady mind wanders, one should subdue it then and there, and bring it back under the control of the Self alone.

The yogī whose mind is fixed on Me verily attains the highest happiness. By virtue of his identity with Brahman, he is liberated; his mind is peaceful, his passions are quieted, and he is freed from sin.

Thus devoting oneself to the Yoga of the Self-realisation, freed from mental impurities, the Yogi easily attains the supreme bliss of union with the Brahman.

With the mind harmonized by Yoga one sees equality everywhere; one sees one’s Self as abiding in all beings and all beings in one’s own Self.

Alternate interpretation
A true yogī observes Me in all beings, and also sees every being in Me. Indeed, the self-realized man sees Me everywhere.

One who always sees me everywhere and sees everything in me, I am never out of sight for him and he never out sight of me.

The Yogi who, established in unity, worships Me dwelling in all beings, he abides in Me, howsoever he may live.

One who, by reason of the identity of Jīvas, sees that pleasure or pain is the same everywhere; that Yogi, O Arjuna, is deemed as the highest.

Alternate meaning
O Arjuna! A devotee of God, who regards the happiness and sorrow of others being in equality with the pleasure and pain of his own self is regarded as Supreme.

This Yoga of equanimity, which has been taught by You, O Krishna, I can not imagine it's steady continuance, because of the restlessness of the mind. For the mind is fickle, O Krishna, turbulent, powerful and stubborn. I deem it as difficult to control the wind.

The mind is undoubtedly hard to subdue and fickle, O mighty-armed one, but, O son of Kunti, by repeated practice and by the exercise of dispassion (detachment) it can be brought under control.

In my opinion, Achieving perfection in Yoga(self-realization is hard to attain by a person of unrestrained mind. But he whose mind is controlled and who strives by right means is assured of success.

Arjuna said: What becomes of that person, O Krishna, who has conviction, but due to the wandering of the mind and the lack of diligent effort, fails to attain perfection in [meditation] Yoga?

O mighty-armed Kṛṣṇa, does not such a man(failed yogi), being deviated from the path of Transcendence, perish like a riven cloud, with no position in any sphere? This doubt of mine, O Krishna, you should remove completely for there is no other than you who can dispel it.

The Blessed Lord said: Neither here [in this world] nor there [in the next], O Arjuna, is there destruction for him. For verily, no one who does good, my son, ever falls.

The unsuccessful yogī, after many, many years of enjoyment on the planets of the pious living entities, is born into a family of righteous people, or into a family of rich aristocracy. Or one is born into a family of wise Yogis; but verily such a birth in this world is very difficult to obtain.

On taking such a birth, he again revives the divine consciousness of his previous life, and he tries to make further progress in order to achieve complete success, O son of Kuru.

By virtue of the divine consciousness of his previous life, he automatically becomes attracted to the yogic principles-even without seeking them. Such an inquisitive transcendentalist, striving for yoga, stands always above the ritualistic principles of the scriptures. But the Yogi striving earnestly, purified of all negative karma, and perfected gradually through many births, reaches the supreme goal.

The Yogi is considered to be superior to the ascetics, superior to the intellectuals, and even superior to the ritualists; therefore, O Arjuna, become a Yogi.

And among all the Yogis and also with all others, one whose inner self is directed to Me,who worships Me with faith — such a one is deemed by Me to be the most accomplished.