The eight limbs of yoga are part of the classical yoga philosophy of Patanjali. He lists and describes them mid way through the second book of the yoga sutras. The first limb is comprised of the yamas, translated as ethical precepts, restraints, or conduct. I think of the yamas as being guidelines to how we act in society, whereas the niyamas (second limb) are personal practices.
Ahimsa, non harming is the first yama. There are 5 of them, and like many other concepts listed in the sutras, the other 4 are refinements of the first one. Non harming or nonviolence is more than the absence of harm. In his book, The Heart of Yoga, TKV Desikachar states that “we must behave with consideration and attention to others. Ahimsa also means acting in kindness towards ourselves.”
Asana practice is an opportunity to practice ahimsa. By attending to the body and breath we refine our poses to minimize harm. By giving others consideration we have the opportunity to show kindness. These practices are simple but not easy. Fortunately, each breath is a chance to try again.