Lord Kṛṣṇa says:
One who performs their prescribed work without expecting the fruits of their action is a true renunciate and a yogī; not one who does not light the sacrificial fire and avoids their duty.

O Arjuna, understand that renunciation is the same as yoga. For no one becomes a true karma-yogī without giving up the desire for pleasure.

For the sage who is still seeking to make progress in yoga, action is said to be the way; when one has become advanced in yoga, renunciation is the way.

When one loses all attachment for sense-objects and to performing action, and when he has abandoned all desires, then he is considered to have reached the heights of yoga.

One should raise oneself by one’s own mind and not allow oneself to fall, for a controlled mind is one’s friend, but an uncontrolled mind is one’s enemy.

The mind is a friend to one who has mastered it. But for one whose mind is uncontrolled, it becomes the worst of enemies.

If one gains self-control and tranquillity, then the Supreme Self is realized. He is perfectly balanced in heat and cold, pleasure and pain, honor and dishonor.

The yogī who is fully content with knowledge and realization of the Self, who dwells in a transcendent state, whose senses are controlled, will see earth, stone, and gold the same.

One who regards well-wishers, friends, an enemy, one who is indifferent, a mediator, the hateful, relatives, and even the righteous and the unrighteous, as the same, is truly advanced.

Remaining alone in a solitary place, controlling his mind and body, free from any desire and sense of ownership, the yogī should constantly engage the mind in meditational absorption.

In a clean place, he should make a firm seat which is neither too high nor too low, covering it with cloth, deer-skin, and kuśa grass.

Sitting on that seat, focusing the mind in concentration, with thoughts and senses restrained, one should practice yoga for self-purification.

He should hold the body, head, and neck erect, in a motionless and steady posture, focusing one’s gaze on the tip of the nose without looking around.

Being serene and fearless, firm in the vow of celibacy, and holding the mind in check, he should fix his thoughts on Me. Sitting in meditation, he should hold Me to be the goal of life.

Applying themselves constantly in this way, the yogī with a controlled mind attains a peace which culminates in liberation, thereby abiding with Me forever.

Arjuna, yoga is not for one who overeats, nor for one who fasts excessively; nor is it for one who sleeps too much, nor for one who stays awake for lengthy periods.

Yoga becomes the destroyer of sorrow for one who is moderate in eating, recreation, the performance of action, sleep, and wakefulness.

When the subdued mind rests in the Self alone, free from all material desire, one is said to be well-established in yoga.

The controlled mind of a yogī who meditates on the Self is compared to a lamp which does not flicker in a windless place.

When the mind, restrained by the practice of yoga, perceives the Self, one discovers Its bliss.

When one experiences that intense joy known to the intellect but unknowable to the senses, one remains fixed in this state, never wavering from it.

When one has attained this state, one realizes there is nothing higher. As a result, one cannot be moved from this position even by terrible suffering.

You should understand that this deliverance from suffering is the very purpose of yoga. Therefore, yoga must be practised with determination and with a mind free from despondency.

It should be done while renouncing all desire for material things and restraining the senses through the mind alone.

With the firm resolution of the intellect, step by step one should become centred within; having focused the mind upon the Self, one should think of nothing else.

Wherever the fickle and unsteady mind wanders, one should bring it back under control, keeping it fixed on the Self alone.

When the yogī has his passions subdued and is focused on the Lord without worldly contamination, when his mind is still, he experiences the highest happiness.

Thus, freed from mental impurities, and constantly engaged in the practice of yoga, the yogī easily attains the supreme bliss of knowing the Lord.

Through this yoga, one gains that equal vision. One sees the Lord in all beings and all beings within the Lord.

For one who sees Me everywhere and everything in Me, I am not separated from him and he is never separated from Me.

However a person lives, if he realises this unity and worships Me as the One dwelling in all beings, he rests in Me as a true yogī.

O Arjuna, one who sees the pleasure and pain of all others as one’s own is the highest yogī.

Arjuna says:
O Kṛṣṇa, due to the mind being so unsteady, this yoga which has been taught by You appears impractical and unstable.

The mind is fickle, turbulent, powerful and stubborn. It is more difficult to control than the wind.

Lord Kṛṣṇa says:
The mind is undoubtedly chaotic and hard to subdue, O Arjuna. But by repeated practise and renunciation it can be brought under control.

In my opinion, it is hard for a person with an unrestrained mind to take up this path. However, it can be done through proper means by one who strives for it with a subdued mind.

Arjuna says:
O Kṛṣṇa, what becomes of that person who has conviction, but due to the wanderings of the mind and lack of diligent effort, fails to attain perfection on this path?

Having no success in both the material world and the path to God, is he not like a broken cloud, lost and without any position?

O Kṛṣṇa, please remove this doubt of mine completely for there is no one else who can dispel it.

Lord Kṛṣṇa says:
Neither in this world nor in the next, O Arjuna, is he ever lost. For verily, no one who does good ever comes to grief.

Having attained to the realms of the righteous and dwelt there for many long years, one who has fallen from yoga is born again in the house of the pure and prosperous.

Or one is born into a family of wise yogīs; but such a birth in this world is very difficult to obtain.

Then, O Arjuna, one regains the same disposition of mind which was acquired in their previous body, and from there one strives again for success in yoga.

Due to the practise done previously he is pulled to that position, even against his will. Understand that one who merely enquires about yoga, transcends the ritualistic principles of the scriptures.

By striving earnestly, the practicing yogīs who are purified of their faults, attain perfection after many births and reach that supreme goal.

The yogī is considered to be superior to those who perform austerity, superior to the intellectuals, and even superior to the ritualists; therefore, O Arjuna, become a yogī.

But more than all the yogīs, he who has faith and worships Me, is deemed by Me to be the highest of all.