According to Osho, a master is an empty, egoless channel—'a hollow bamboo'—through whom the divine acts; he is no-mind, a doorway to depth, and his loving presence heals without trying. A psychotherapist is a knowledgeable doer who works on the surface of mind, applying techniques; helpful for adjustments, yet limited, sharing the patient’s level and unable to reach the existential core.
A master lets the divine heal your deepest self, while a therapist uses mind-knowledge to fix surface problems.