By guarding your speech and actions they become graceful and pleasing to the eye and ear, while you yourself remain comfortable and at ease within the restraint. All your behaviour, manners, movements and speech become beautiful, because you are taking care to reflect upon, adjust and correct your behaviour. You can compare this with your dwelling place or the meditation hall. If you are regularly cleaning and looking after your dwelling place, then both the interior and the area around it will be pleasant to look at, rather than a messy eyesore. This is because there is someone looking after it. Your actions and speech are similar. If you are taking care with them, they become beautiful, and that which is evil or dirty will be prevented from arising.
– Ajahn Chah, The Path to Peace