In English
Why do we ask people to sit straight and to sit quiet in meditation? Because when the body is straight and quiet, the mind inside is also straight and quiet. If you cannot control your body, how can you control your mind? The FIRST thing is to control your body by having all the limbs and body organs in a steady manner. The basis for the mind wandering is that your physical body is also continually wandering. So the first thing you have to do is to give up this continual wandering of the physical body.