In order to have a pure mind, you must first work on the karma of your body and mouth. Some might say, “It is good enough for a person to have a good heart.” Of course you must have a good heart, but what kind of action can show that? Your good deeds are evidence of your good heart. If you do not pay attention to the karma of your mouth, do not do good deeds and instead do bad deeds, how can you lie that you have a good heart?