The first limb consists of the yamas, or universal ethical observances. The Sanskrit term yama more specifically translates as "bridle" or "rein". Just as a rider places a rein on a horse to steer the animal in the proper direction, the yamas are restraints that we willingly and intentionally place upon ourselves in order to direct our efforts towards creating a full, happy and meaningful life.
The first yama is ahimsa, or nonviolence. In its most literal sense, nonviolence may be interpreted as not hurting or killing other people. Most of us don't need to muster up too much discipline to refrain from murdering our neighbor. But to truly embody ahimsa we must extend past this literal interpretation to include not just these violent actions but also thoughts, feelings, and words. We must pay constant attention to our propensities towards unkind behavior, harmful thought, and hurtful speech. We must practice compassion towards all living beings.
Many yogis practice ahimsa by eating a vegetarian diet. They believe that killing another living being for any reason, including one's own sustenance, is a violation of the first yama. Others adopt a looser interpretation: they choose to eat meat mindfully by investigating where and how the animals they eat are raised and supporting farms that cause the least amount of animal suffering and environmental devastation.
Whichever interpretation one chooses, in practicing ahimsa it’s necessary to examine one's choice to eat or not eat meat and to acknowledge, honor and respect the suffering of animals that surrender their lives for human consumption.
Nonviolence as a practice is not just outwardly focused. We must also turn in upon ourselves and treat ourselves with kindness and compassion. For some this may prove even more formidable than being kind and loving towards others.
This is a challenge that often comes up on the mat. You may find yourself constantly pushing yourself to work harder, to stretch further, to go beyond your edge in a constant pursuit of perfection and progress. This kind of striving is a form of aggression and violence towards oneself.
If you observe this tendency in yourself, work towards awareness rather than aggression. When you feel the urge to mindlessly push past your boundaries, consciously pull back and tune in to what's going on in the moment. When you feel compelled to do something your body's fighting against, see if you can stay in that space just before you reach your edge rather than pushing beyond it.
This doesn't mean you should be complacent or lackadaisical; on the contrary, you must be constantly aware and attuned to where your edge is in each moment. Your edge is that place where you move away from your comfort zone and challenge yourself, but can still maintain your alignment, your skill, and a calm, steady breath. Mindfulness of one's edge is key to practicing ahimsa on the mat.
The most important quality of ahimsa is not the negative injunction not to kill but its broader positive message of love. Love towards oneself and all beings is the very first step and the foundation for the entire philosophical system of classical yoga.