The eight-limbed path of yoga
The word Ashtanga means eight limbs, or steps (ashta=eight, anga=limb). These are noted in the classic Indian text the Yoga Sutras, composed by a sage named Patanjali around two thousand years ago. The Yoga Sutras, a collection of 196 aphorisms on yoga, are divided into four books. Book two, sadhana pada, outlines the eight-fold path.
THE EIGHT LIMBS OF YOGA: yama—moral codes or restraints; how we relate to others niyama—observances or commitments; how we relate to ourselves asana―physical posture of yoga pranayama―control of the breath, or prana (life force) pratyahara―withdrawal of the senses; turning attention inward with conscious detachment from external influences dharana―concentration, holding steady focus dhyana―meditation, uninterrupted flow of one-pointed concentration samadhi―complete absorption and deep realization
THE FIVE YAMAS: ahimsa―non-violence in words, thoughts and actions satya—truthfulness, following a true and honest path asteya―non-stealing, not taking property, wealth, ideas, or anything that does not rightfully belong to us brahmacharya―sexual conservation, respecting the fidelity of relationships aparigraha―non-grasping, not clinging to things, live without greed THE FIVE NIYAMAS: saucha―cleanliness, both inside and out, purity of mind, body and speech santosha―contentment, being happy with what we have, unshakable acceptance tapas―self-discipline, the cleansing heat generated during practice, burning off impurities svadhyaya―self-study, introspection, deepening understanding of yogic teachings and texts Ishvara pranidhana―devotion, or surrender, to God We begin with the first four limbs...refining our behavior through yama and niyama, our body through asana, and our breath through pranayama. Gradually moving towards the remaining, more spiritual, limbs.
The yamas and niyamas are the moral backbones of yoga. Simply put, the yamas are things not to do, or restraints. The niyamas are things to do, or observances. When practiced, we live more virtuously.
By practicing and living these principles in our daily life, the teachings become a greater gift. One can begin to see yoga as more than a physical practice, and know the wisdom of the ancient tradition.
References: Astanga Yoga Anusthana, R. Sharath Jois.