"There is no treasure on earth, which can pay the debt, that the disciple has with his guru; for having taught him even if it was only a letter. Just as the man finds underground water using a palm, the student acquires the knowledge that his preceptor possesses through the service that he gives him. The evil of heart, will not reach holiness even if he is instructed in many ways, and the nim tree will not become sweet even if he irrigates it with milk and ghee from the cup to the roots."