"How to Purify One's Morality"
by ven. Ajahn Chah

Morality is restraint and discipline of body and speech. On the formal level this is divided into classes of precepts for lay people and for monks and nuns. However, to speak in general terms, there is one basic characteristic - that is INTENTION. When we are mindful or self-recollected, we have right intention. Practising self-recollection and mindfulness will generate good morality.
It is only natural that when we put on dirty clothes and our bodies are dirty, that our minds to will feel uncomfortable and depressed. However, if we keep our bodies clean and wear clean, neat clothes, it makes our minds light and cheerful. So too, when morality is not kept, our bodily actions and speech are dirty, and this is a cause for making the mind unhappy, distressed and heavy. We are separated from right practice and this prevents us from penetrating into the essence of the Dhamma in our minds. The wholesome bodily actions and speech themselves depend on mind, properly trained, since mind orders body and speech. Therefore we must continue practice by training our minds.