The practice of yoga is an art and science dedicated to creating union between body, mind and spirit.
Its objective is to assist the practitioner in using the breath and body to foster an awareness of ourselves as individualized beings intimately connected to the unified whole of creation.
In short it is about making balance and creating equanimity so as to live in peace, good health and harmony with the greater whole.
This art of right living was perfected and practiced in India thousands of years ago and the foundations of yoga philosophy were written down in The Yoga Sutra of Patanjali, approximately 200 AD.
This sacred text describes the inner workings of the mind and provides an eight-step blueprint for controlling its restlessness so as to enjoying lasting peace.
The core of Patanjali’s Yoga Sutra is an eight-limbed path that forms the structural framework for yoga practice.
Upon practicing all eight limbs of the path it becomes self-evident that no one element is elevated over another in a hierarchical order.
Each is part of a holistic focus which eventually brings completeness to the individual as they find their connectivity to the divine.
Because we are all uniquely individual a person can emphasize one branch and then move on to another as they round out their understanding.
In brief the eight limbs, or steps to yoga, are as follows:
Yama : Universal morality
Niyama : Personal observances
Asanas : Body postures
Pranayama : Breathing exercises, and control of prana
Pratyahara : Control of the senses
Dharana : Concentration and cultivating inner perceptual awareness
Dhyana : Devotion, Meditation on the Divine
Samadhi : Union with the Divine
The first two limbs that Patanjali describes are the fundamental ethical precepts called yamas, and the niyamas.
These can also be looked at as universal morality and personal observances.
Yamas and niyamas are the suggestions given on how we should deal with people around us and our attitude toward ourselves.
The attitude we have toward things and people outside ourselves is yama, how we relate to ourselves inwardly is niyama.
Both are mostly concerned with how we use our energy in relationship to others and to ourselves.
The yamas are broken down into five "wise characteristics."
Rather than a list of dos and don’ts, "they tell us that our fundamental nature is compassionate, generous, honest and peaceful."
They are as follows:
I. Yamas (Universal Morality)
1. Ahimsa – Compassion for all living things
The word ahimsa literally mean not to injure or show cruelty to any creature or any person in any way whatsoever. Ahimsa is, however, more than just lack of violence as adapted in yoga. It means kindness, friendliness, and thoughtful consideration of other people and things. It also has to do with our duties and responsibilities too. Ahimsa implies that in every situation we should adopt a considerate attitude and do no harm.
2. Satya – Commitment to Truthfulness
Satya means "to speak the truth," yet it is not always desirable to speak the truth on all occasions, for it could harm someone unnecessarily. We have to consider what we say, how we say it, and in what way it could affect others. If speaking the truth has negative consequences for another, then it is better to say nothing. Satya should never come into conflict with our efforts to behave with ahimsa. This precept is based on the understanding that honest communication and action form the bedrock of any healthy relationship, community, or government, and that deliberate deception, exaggerations, and mistruths harm others. ii
3. Asteya - Non-stealing
Steya means "to steal"; asteya is the opposite-to take nothing that does not belong to us. This also means that if we are in a situation where someone entrusts something to us or confides in us, we do not take advantage of him or her. Non-stealing includes not only taking what belongs to another without permission, but also using something for a different purpose to that intended, or beyond the time permitted by its owner.iii The practice of asteya implies not taking anything that has not been freely given. This includes fostering a consciousness of how we ask for others’ time for inconsiderate behavior demanding another’s attention when not freely given is, in effect, stealing.
4. Brahmacharya - Sense control
Brahmacharya is used mostly in the sense of abstinence, particularly in relationship to sexual activity. Brahmacharya suggests that we should form relationships that foster our understanding of the highest truths. Brahmacharya does not necessarily imply celibacy. Rather, it means responsible behavior with respect to our goal of moving toward the truth. Practicing brahmacharya means that we use our sexual energy to regenerate our connection to our spiritual self. It also means that we don’t use this energy in any way that might harm others.iv
5. Aparigraha - Neutralizing the desire to acquire and hoard wealth
Aparigraha means to take only what is necessary, and not to take advantage of a situation or act greedy. We should only take what we have earned; if we take more, we are exploiting someone else. The yogi feels that the collection or hoarding of things implies a lack of faith in God and in himself to provide for his future.v Aparigraha also implies letting go of our attachments to things and an understanding that impermanence and change are the only constants.
The Yoga Sutra describes what happens when these five behaviors outlined above become part of a person's daily life. Thus, the yamas are the moral virtues which, if attended to, purify human nature and contribute to health and happiness of society.
Source: http://www.expressionsofspirit.com/yoga/eight-limbs.htm