Ashtang Yoga – A way to enlightenment

Maharishi Patanjali has defined Yoga as "the detention of the thoughts of the mind". In Yoga Sutra, he explained in detail the path of Yoga with eight limbs for full wellness and physical, mental and spiritual purification. Ashtang-Yoga is eight dimensional paths:

(Yoga Sutra 29 - यमनियमासनप्राणायामप्रत्याहारधारणाध्यानसमाधयोऽष्टाव अङ्गानि ॥) i.e. Yama, Niyama, Asana, Pranayama, Pratyahara, Dharna, Dhyana and Samadhi are eight limbs of yoga.

The Yama and Niyama are moral trainings; without Pratyâhâra, or restraint of the senses from their objects; Dhâranâ, or fixing the mind on a spot; Dhyâna, or meditation; and Samâdhi, or superconsciousness. The mind can exist on a still higher plane, the superconscious. The three — Dharana, Dhyana, and Samadhi — together, are called Samyama.

Ashtang Yoga impacts Panch Kosh. Yama, Niyama and Asana on Annmya Kosh, Pranayama on Pranamaya Kosh, Dharna & Dhyana on Manomaya Kosh & Vigyanmaya Kosh and Samadhi on Annandamaya Kosh.
Shree Krishna in Bhagavad Gita has explained the concepts of yogic ideals in its chapter 6 & 8 and stressed that one who abandon the body & mind while contemplating the Nirgun Brahma, that man achieves the eternal divine.

Eight limbs of Ashtang yoga and path shown by Shree Krishna are given hereunder:

I. Yama: Five Social Ethics – how to behave in External environment. 

(Yoga Sutra 30 - अहिंसासत्यास्तेयब्रह्मचर्यापरिग्रहा यमाः ॥)
i.e. Ahimsa (Non-violence), Satya (Truthfulness), Asteya (Non-stealing), Brahmacharya (Chastity) and Aparigraha (Non-accumulating)

1. Ahimsa - not injuring or harming people with words, thoughts or actions;
2. Satya - Truth in thoughts, staying in the supreme truth; (If I tell a lie, or cause another to tell one, or approve of another doing so, it is equally sinful. Every vicious thought will rebound),
3. Asteya (i.e. not taking others’ goods by stealth or by force),  
4. Brahmacharya - Continence i.e. self-control, chastity by thought, word and deed and stabilizing Consciousness in the Knowledge of Spirit & Restraint in all the sensory-borne pleasures;
5. Aparigraha - not accumulating excess and not wanting the things of others or not receiving of any gifts from others. With every gift, he is likely to receive the evils of others.​

II. Nyama (Rule): Five Personal Ethics – how to behave with body & mind and to discipline them. 
(Yoga Sutra 32 - शौचसंतोषतपःस्वाध्यायेश्वरप्रणिधानानि नियमाः ॥)

i.e. Shaucha (purity or cleanliness), Santosha (contentment), Tapas   (austerity), Svâdhyâya (study) and Ishvara-pranidhâna (worshipping and self-surrender God).

1. Shaucha - Purification of Body and Mind; both external & internal. By the practice of cleanliness, the Sattva material prevails, and the mind becomes concentrated and cheerful.
2. Santosha - be contented and happy;
3. Tapas - being self-discipline.
4. Svadhyaya – Study of Sattva material i.e. Vedas, Bhagvat Geeta  and other such books.
5. Ishwar-Pramanidhi - complete devotion to God.

III.Asana : Body postures or Yogasons to make body & mind stable, tranquil and healthy.

1. It is leaving the body free, holding the chest, shoulders, and head straight. Be seated firmly in comfortable posture so that body remains stable for long period.

1. When you have succeeded in conquering the body and keeping it firm, your practice will remain firm, but while you are disturbed by the body, your nerves become disturbed, and you cannot concentrate the mind.

IV.Pranayama : Prana means the vital forces in one's own body, Âyâma means controlling them.
 
It is control of life force by breathing techniques. First, it purifies the nerves. Shankaracharaya in his commentary on the Shvetâshvatara Upanishad quoted: "The mind, whose dross has been cleared away by Pranayama, becomes fixed in Brahman.
[Stopping the right nostril with the thumb, through the left nostril fill in air, according to capacity; then, without any interval, throw the air out through the right nostril, closing the left one. Again inhaling through the right nostril eject through the left.]

V.Pratyahara (Withdrawal): means, "gathering towards," checking the outgoing powers of the mind, freeing it from the control of the senses. 
One who has succeeded in attaching or detaching his mind to or from the centres at will.
The human mind is like that monkey, incessantly active by its own nature. If one can restrain the mind-stuff or chitta and keep it calm, this is called Pratyahara. One should simply watch the thoughts. Gradually, these will subsidise.

VI. Dharna (Perception): To make mind stable and being concentrated 
 
To hold the mind on certain part of the body to the exclusion of others
 
VII.Dhayan (Meditation): constant meditation.
 
When one has so intensified the power of Dhyana as to be able to reject the external part of perception and remain meditating only on the internal part, the meaning, that state is called Samadhi. Only one wave is left in the mind.

We have, then, two planes in which the human mind works. First is the conscious plane, in which all work is always accompanied with the feeling of egoism. Next comes the unconscious plane, where all work is unaccompanied by the feeling of egoism. There is a still higher plane upon which the mind can work i.e. above consciousness. It is called Samâdhi or superconsciousness. Unconscious, conscious, and superconscious states — belong to one and the same mind. There are not three minds in one man, but one state of it develops into the others.

When a man goes into deep sleep, he enters a plane beneath consciousness. He works the body all the time, he breathes, he moves the body, perhaps, in his sleep, without any accompanying feeling of ego; he is unconscious, and when he returns from his sleep, he is the same man who went into it. The sum total of the knowledge which he had before he went into the sleep remains the same; it does not increase at all. No enlightenment comes.

VIII.Samadhi (Kavaliya): Perfect concentration, Connecting to the soul: beyond the words, limits of reason, state of trance.
 
When mind itself is the object of meditation. If the mind can be fixed on the centre for twelve seconds it will be a Dharana, twelve such Dharanas will be a Dhyana, and twelve such Dhyanas will be a Samadhi.
In Samadhi, all the tendencies which become waves are eliminated.

Sri Krishna in Bhagavad Gita has explained the concepts of yogic ideals in chapter 6 & 8 as under: 

1. योगी युञ्जीत सततमात्मानं रहसि स्थितः।एकाकी यतचित्तात्मा निराशीरपरिग्रहः (verse 10॥ chapter 6)

Aspirant (Yogi) to withdraw and hold mind and senses, sit in solitary place and put attention of soul into eternal divine.

1. तत्रैकाग्रं मनः कृत्वा यतचित्तेन्द्रियक्रियः।उपविश्यासने युञ्ज्याद्योगमात्मविशुद्धये ॥(verse 12॥ chapter 6)

By sitting in that seat, keeping the mind and actions of the senses under control, practice yoga for purification of interaction by integrating the mind.

1. समं कायशिरोग्रीवं धारयन्नचलं स्थिरः ।
   सम्प्रेक्ष्य नासिकाग्रं स्वं दिशश्चानवलोकयन्‌ ॥(verse 13॥ chapter 6)

He should keep body, head and neck stable and look at the face of the nostrils without looking at other directions.

1. युञ्जन्नेवं सदात्मानं योगी नियतमानसः। शान्तिं निर्वाणपरमां मत्संस्थामधिगच्छति ॥(verse 15॥ chapter 6)

Yogi who keeps check on mind and continuously put soul in eternal divine, gets the ultimate peace of ecstasy.

1. प्रयत्नाद्यतमानस्तु योगी संशुद्धकिल्बिषः। अनेकजन्मसंसिद्धस्ततो यात परां गतिम्‌ ॥ (verse 45॥ chapter 6)

Such Yogi who has been practicing effortlessly, is completely free from all sins of past many lives in this life only and attains Paramagti (no rebirth takes place).

1. प्रयाण काले मनसाचलेन भक्त्या युक्तो योगबलेन चैव ।
   भ्रुवोर्मध्ये प्राणमावेश्य सम्यक्‌- स तं परं पुरुषमुपैति दिव्यम्‌ ।(verse 10॥ chapter 8)

Yogi, who establishes attention between eyebrows and remembers the eternal divine with great devotion & stable mind, reaches to eternal divine only.

1. सर्वद्वाराणि संयम्य मनो हृदि निरुध्य च । मूर्ध्न्याधायात्मनः प्राणमास्थितो योगधारणाम्‌ ॥ओमित्येकाक्षरं ब्रह्म व्याहरन्मामनुस्मरन्‌ । यः प्रयाति त्यजन्देहं स याति परमां गतिम्‌ ॥ (verse 12-13॥ chapter 8)

Yogi who by blocking the gates of all the senses, with stable mind, put attention of eternal divine on forehead and continuously repeats “Aum”, he achieves eternal divine. (i.e. abandon the body & mind while contemplating the Nirgun Brahma, that man achieves the eternal divine).
 
General Guidelines
Do’s

1. It must be done scientifically, slowly, by regular practice, under guidance of enlightened guru and we must cast off all superstition.
2. When you practice, first salute all the ancient Yogis, and your own Guru, and God, and then begin.

 
Don’t

1. It must not be practiced where is too much noise or many wicked persons or dirty place.
2. It should be done when ill, or when the mind is very miserable and    sorrowful.

 
Reference:

1. Complete works by Swami Vivekananda Volume I