In Buddhism, the Buddha-nature which lies within us all is often compared to a seed. From this point of view the master can be compared to a gardener who, being aware of the tremendous richness contained in the seed, takes great care of it to make it grow. When based on mutual trust, the master-disciple relationship gives the disciples access to a space where they can be set free from the limited representation of themselves that they acquired from their parents, their culture, society, and their own individual karma.
From an ultimate point of view, our highest potential is nothing but our true nature, which is called in Zen Buddha-nature. Becoming a disciple means understanding and accepting the need to be assisted by a third party – in this case the master - to actualize this tremendous potential. If we forget our ultimate vocation, which is to realize Buddhahood, the master is there to remind us of it. This is achieved through his teaching, through the fact that he is constantly looking out for possible openings in the minds of the disciples towards what lies beyond the sphere of the ego, and through his mere presence which, for a disciple, can be a living reminder of what is essential.