The Foundation of Yoga Practice

Yama are great universal vows, to be practiced and observed continuously without break regardless of the varying circumstances of time, place, or social status. Their cultivation purifies the mind.

Niyama are self-disciplines that, when observed, lead to success in Yoga.

They are lifelong disciplines that must be practiced sincerely and continuously by thought, word, and deed — One will not succeed without these as the foundation of Yoga practice. They are the basis of all yoga practices, and are defined in the eight-limbs or ashtanga or Raja Yoga.

Yama (abstinence):

control of actions, words, and thoughts in relation to others
Ahimsa (non-violence): to not injure any being
Satya (truthfulness): to speak only the truth; to be sincere and honest
Asteya (non-stealing): to not steal anything
Aparigraha (non-greed): to possess no more than one's minimum need; to abstain from receiving gifts
Brahmacarya (continence): to be chaste

Niyama(observance):

practices in relation to oneself through discipline in actions, words, and thoughts

Sauca (purity): to maintain the purity of the mind and body
Santosha (contentment): to discern and realize only the bare minimum sufficient for living
Tapas (austerity): to conquer all physiological and psychological dualistic conditions, such as heat and cold, like and dislike, comfort and discomfort
Svadhyaya (study of sacred scriptures): to cultivate one's understanding of the Truth
Isvarapranidhana (faith and commitment to a personal god): pure faith in God; the vow to realize the Truth.