More than this, there is an exchange of spiritual vibrations. Just by study or practice you cannot realize this truth, this feeling, this peace, this joy which is beyond words, which belongs to being your self, your natural self. In the East this is called Tawajjeh, which means presence, contact, association with. It is in this way that you learn what cannot be learned in any other way. Thus the disciples of Jesus Christ learned by his presence what no study or practice would ever have taught them. And in Mohammed's time his disciples Ali and Abu Bakr gained very great benefit from his presence.