In the practice of the way to Enlightenment, people see the Buddha with their own eyes and believe in Buddha with their own minds. The eyes that see Buddha and the mind that believes in Buddha are the same eyes and the same mind that, until that day, had wandered about in the world of birth and death.
If a king is plagued by bandits, he must find out where their camp is before he can attack them. So, when a man is beset by worldly passions, he should first ascertain their origins.
When a man is in a house and opens his eyes he will first notice the interior of the room and only later will he see the view outside the windows. In like manner they can not have the eye notice external things before there is recognition by the eye of the things in the house.
If there is a mind within the body, it ought first to know the things inside the body; but generally people are interested in external things and seem to know or care little for the things within the body.
If the mind is located outside the body, it should not be in contact with the needs of the body. But, in fact, the body feels what the mind knows, and the mind knows what the body feels. Therefore, it can not be said that the human mind is outside of the body. Where, then, does the substance of the mind exist?