TThe Vyasa-Gita is contained in chapters 126 to 137 of Brahmapurana (Part III).
The sages said:
Now tell us the yoga which is an antidote to the contact with miseries. On understanding it, we shall come in unison with the unchanging Purushottama (the Eternal Supreme Soul).
On hearing their words, the highly delighted Krisna-Dvaipayana, the Yogi, the most excellent among those who understand yoga, said thus:
O Brahmins! Listen.I shall recount yoga that destroys worldly existence. By practising it, a yogi shall attain to liberation which is extremely difficult to access.
At the outset, the devotee (seeker) shall propitiate the preceptor devoutly and listen to the yogic scriptural texts.He must then dfficiently master Itihasa, Purana and Veda.
The intelligent one shall fully understand the diet (of a yogi), the pitfalls during the practice of yoga, and the proper time and place for the same. He shall be free of the influence of the pairs of opposites. He shall desist from hoarding possessions, and then practise yoga. Flour of fried grains, rice gruel, butter-milk, roots, fruits, milk, barley food, ears of corn and oil cakes are conducive to the steady practice of yoga.
One shall never practise yoga when the mind is unhappy, when one is (excited), weary or hungry, when the mutually conflicting pairs of opposites are present, when it is very cold, when it is very hot, and when there is too much of wind.
One shall not practise yoga in a place which is very noisy, close to water or near fire. One shall not practise it in a dilapidated cow-pen, a cross-road, a place infested by reptiles, a cremation ground, or on the banks of a river. One shall not practise in a monastery, an anthill, a dangerous place or near a well. One shall not practise it on a heap of dry leaves. If, out of foolishness, anyone were to practise yoga without taking into consideration the above restrictions as to places, certain defects arise causing obstacles. I shall describe them. Deafness, sluggishness, loss of memory, dumbness, blindness and fever are produced immediately. Similarly ignorance is caused.
Hence (arrangement for) safety should always be made in every possible way by a person conversant with yoga, since the physical body is the means to achievement of virtue, wealth, love and liberation.
A lonely hermitage, a secret place (one with privacy), a place free from noise, fear and (unnecessary) movements, a clean vacant house and a beautiful secluded temple are the suitable places for the practice of yoga.
The first or the last yama (a period of three hours) of the night or in the forenoon or at midday is the right time for practice of yoga.
A devotee shall keep his mind pure and well-concentrated. His diet shall be proper. He shall control his sense-organs.
He shall be seated facing east on a beautiful seat that is comfortable and steady. It shall be neither too raised up, nor too much depressed.
The devotee shall be pure, truthful in speech and devoid of desire. He shall observe moderate periods of sleep. He shall subdue anger. He shall be engaged in what is conducive to the welfare of living beings. He shall put up with the inconvenience of suffering the pairs of opposites (such as excessive heat and severe cold). He shall be self-possessed. He shall keep his body, legs and head in a steady posture.
He shall place both the hands on the navel. He shall be calm. He shall be seated in the lotus posture. The eyes should be fixed on the tip of the nose. He shall control his vital airs and speech. All the sense organs with the mind shall be withdrawn into the heart(soul or spirit).Otherwise silent, he shall utter the Pranava (Aum) continuously with the mouth well-covered. He shall be steady.
He shall subdue the activities of tamas by means of rajas and those of rajas by means of sattva. He shall maintain a pure and quiet posture with the eyes closed. (Thus) the practitioner of yoga shall always be in unison with Purushottama, the bestower of salvation, who dwells in the cavity of his lotus-like heart, who is Omnipresent and who is Unsullied.
At the outset, he shall fix the sense organs, the organs of action and the elements in his soul. He shall unite his soul with the Supreme Soul. It is then that the devotee (seeker) performs yoga.
The supreme region is characterized by the hundredth part of the tip of a hair (that is, it is very subtle). The yogi devoted to meditation sees it by the lamp of his mind. The practitioner of yoga becomes capable of withdrawing the sense organs like a turtle that withdraws its limbs under its back.
If the mind of a person is able to find its ultimate end in the Supreme Soul after abandoning all sensuous objects, his success in yoga is assured.
When the mind is free from sensuous objects as the yogi is in communion with the Supreme Brahman in the course of his ecstatic experience, and the mind gets dissolved in the Supreme Brahman, he attains to the highest state of bliss.
When the mind of the yogi is disengaged from every sort of activity after attaining to the highest state of bliss, he attains to salvation.
By the power of yoga, the yogi attains to the Pure Purushottama who is termed the fourth state of consciousness that transcends the three preceding states (awake, dream and deep-sleep states). There is no doubt that the yogi is liberated.
A yogi who is free of desires for any object of lust, who is pleasing to look at in any posture whatsoever (or who sees pleasant things every where), and who is aware of transience of everything shall be liberated and not otherwise.
He who is conversant with yoga shall not indulge in the objects of senses. With absence of attachment to any objects and regular practice of yoga, he shall get undoubtedly liberated.
Yoga is not achieved merely by resorting to the lotus posture or by concentrating on the tip of the nose. The unison (sublation) of the mind and the sense-organs with the soul is called yoga.