Intellectual study may last the whole life, there is no end to it. This is why the teacher does not encourage speculation. A doctrine means a separation from other doctrines. The Sufi belongs to every religion. The Sufi has no special beliefs or speculations. There can, for instance, be one Sufi who believes in reincarnation and another who realizes Heaven and Hell. The work of the Sufi is personal development. It is what you practice that is important rather than what the teacher says. The teacher can give you protection. The teacher can say, "Yes, it is so, it is my experience also."