Foundations of Yoga, Part 1: Yama and Niyama

Prerequisites for yoga
"Knowledge (Jnana) does not come about from practice of yoga methods alone. Perfection in knowledge is in fact only for those who begin by practice of virtue (dharma). Yet, without yoga as a means, knowledge does not come about. The practice of yogic methods is not the means by itself, yet it is only out of that practice of yoga that the perfection in knowledge comes about. And so it is said by the teachers: 'Yoga is for the purpose of knowledge of truth'" Thus wrote Shankara.
All things rest upon something else-that is, all things are supported by another. This is because a foundation is needed for anything to exist. Being Himself the Ultimate Support of all things, God alone is free from this necessity. Yoga, then, also requires support. As Trevor Leggett says in his introduction to Shankara's commentary on the Yoga Sutras: "This is yoga presented for the man of the world, who must first clear, and then steady, his mind against the fury of illusory passions, and free his life from entanglements." Patanjali very carefully and fully outlines the elements of the support needed by the aspirant, giving invaluable information on how to guarantee success in yoga.
The first Yoga Sutra says: "Now the exposition of yoga," implying that there must be something leading up to yoga in the form of necessary developments of consciousness and personality. These prerequisites may be thought of as the Pillars of Yoga, and are known as Yama and Niyama.
Yama and Niyama
Yama and Niyama are often called "the Ten Commandments of Yoga." Each one of these Five Don'ts (Yama) and Five Do's (Niyama) is a supporting, liberating Pillar of Yoga. Yama means self-restraint in the sense of self-mastery, or abstention, and consists of five elements. Niyama means observances, of which there are also five. Here is the complete list of these ten Pillars as given in Yoga Sutras 2:30,32:
1) Ahimsa: non-violence, non-injury, harmlessness
2) Satya: truthfulness, honesty
3) Asteya: non-stealing, honesty, non-misappropriativeness
4) Brahmacharya: sexual continence in thought, word and deed as well as control of all the senses
5) Aparigraha: non-possessiveness, non-greed, non-selfishness, non-acquisitiveness
6) Shaucha: purity, cleanliness
7) Santosha: contentment, peacefulness
8) Tapas: austerity, practical (i.e., result-producing) spiritual discipline
9) Swadhyaya: introspective self-study, spiritual study
10) Ishwarapranidhana: offering of one's life to God
All of these deal with the innate powers of the human being-or rather with the abstinence and observance that will develop and release those powers to be used toward our spiritual perfection, to our self-realization and liberation.
These ten restraints (yama) and observances (niyama) are not optional for the aspiring yogi-or for the most advanced yogi, either. Shankara states quite forcefully that "following yama and niyama is the basic qualification to practice yoga." Mere desire and aspiration for the goal of yoga is not enough, so he continues: "The qualification is not simply that one wants to practice yoga, for the sacred text says: 'But he who has not first turned away from his wickedness, who is not tranquil and subdued, or whose mind is not at rest, he can never obtain the Self by knowledge.' (Katha Upanishad 1.2.24) And in the Atharva text: 'It is in those who have tapas [strong discipline] and brahmacharya [chastity] that truth is established.' (Prashna Upanishad 1:15)And in the Gita: 'Firm in their vow of brahmacharya.' (Bhagavad Gita 6:14) So yama and niyama are methods of yoga" in themselves and are not mere adjuncts or aids that can be optional.
But at the same time, the practice of yoga helps the aspiring yogi to follow the necessary ways of yama and niyama, so he should not be discouraged from taking up yoga right now, thinking that he should wait till he is "ready" or has "cleaned up his act" to practice yoga. No. He should determinedly embark on yama, niyama, and yoga simultaneously. Success will be his.