"Yama" has different meanings. It may mean "rein, curb, or bridle, discipline or restraints" In the present context, it is used to mean "self-control, forbearance, or any great rule or duty". It can also be interpreted as "attitude" or "behavior". Certainly a particular attitude can be expressed as discipline, which then influences our behavior. Patanjali's Yoga Sutra mentions five different yama, that is, behavior patterns or relationships between the individual and the outside world.

The prescribed rules are:

Ahimsa (Harmlessness)

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. It could even mean that we must fight if our life is in danger. Ahimsa implies that in every situation we should adopt a considered attitude.

Satya (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. The Mahabharata, the great Indian epic, says: "Speak the truth which is pleasant. Do not speak unpleasant truths. Do not lie, even if the lies are pleasing to the ear. That is the eternal law, the dharma." Please note that this does not mean speak lie. Keeping quiet and saying lies are two different things.

Asteya (Non-stealing)

Asteya is the third yama. 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. We are to refrain from taking that which is not ours by right of consciousness and karma.

Brahmacharya (Sense-control)

Brahmacharya is a movement toward the essential truth. It 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. If sensual pleasures are part of those relationships, we must take care that we keep our direction and do not get lost. Avoid relationships that makes us deviate from finding the eternal truth. On the path of serious, constant searching for truth, there are certain ways of controlling the perceptual senses and sexual desires. Brahmacharya does not necessarily imply celibacy. Rather, it means responsible behavior with respect to our goal of moving toward the truth.

Aparigraha (Neutralizing the desire to acquire and hoard wealth)

The last yama is aparigraha, a word that means something like "hands off" or "not seizing opportunity." Parigraha means "to take" or "to seize." 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. In addition, unearned rewards can bring with them obligations that might later cause problems.

The Yoga Sutra describes what happens when these five behaviors outlined above become part of a person's daily life. For example, as we develop ahimsa (kindness and consideration), our presence will create pleasant and friendly feelings in those around us. And if we remain true to the idea of satya, everything we say will be truthful. We will become trustworthy. In India, one's word is considered one's biggest asset. The Yoga Sutra also states that a person who is firmly anchored in asteya will receive all the jewels of this world. Such a person may not be interested in material wealth, but he or she will have access to the finest things in life.

The more we recognize and search for the meaning of the essential truth, the less will we be distracted by other things. Certainly it requires great strength to take this path. The Yoga Sutra teaches that the more faith we have, the more energy we have. At the same time we also have more strength to pursue our goals. So the more we seek the truth in the sense of brahmacharya, the more vitality we will have to do so.

Parigraha is the increasing orientation toward material things. If we reduce parigraha and develop aparigraha, we are orienting ourselves more inwardly. The less time we spend on our material possessions, the more we have to spend on investigating all that we call yoga. We will learn to enjoy what we have rather than constantly seeking things we don't have and never getting satisfied in life. It is a scientific fact that the more money and material possessions we have, the more stressful we become.

Thus, the yamas are the moral virtues which, if attended to, purify human nature and contribute to health and happiness of society.