The yamas are part of the 8 limbs of Raja Yoga which help purify the mind and body.
It is a list of things not to do, to help destroy the lower nature.
The first one is Ahimsa, meaning Non-violence, Non-Injury.
This is not only for the physical body, but also consider the thoughts you think.Wanting to elbow that person in the train, or yell at someone for not doing what you want them to do.Forcing, pushing and pushing and pushing yourself, into a posture you are not ready to do yet.
Your words, thoughts, feelings and actions.
Even if you don’t voice them, it sends a energy through out your body.We need to be kind, loving, and caring, to ourselves, and others.With our thoughts, feelings, words and actions.