While we need not rack our heads too much in the analysis of all the minutiae involved in the observance of purity through the various vestures of the personality, we may in broad outline conclude that purity means the cleanliness of the body, the speech and the mind. In body, in speech and in mind, we have to be pure. People generally understand, by physical purity, not only a clean body, but also clean clothing, and a clean atmosphere. This physical purity is comparatively easy to maintain. Verbal purity is difficult, and more difficult still is mental purity or psychological purity.
Mental purity is almost impossible for ordinary persons.
One can behave badly in human society in spite of being a very clean person physically and in household surroundings. Any kind of injury inflicted upon another by harsh speech is not called for in the context of the observance of Saucha through speech. Ahimsa is the supreme virtue, finally speaking. Everything comes under that. All other principles of Yama and Niyama fall under the shelter of this vast, comprehensive principle called Ahimsa, a thing which is very hard to understand, but which is the most important of all canons or prescriptions or standards of behaviour.