The Prophet (S) has stated that...
The Prophet (S) has stated that, “If there is a person who is not worthy of gaining a (particular) knowledge, then you must not teach it to him since when knowledge falls into his hands, he will use it in the wrong way and will lead the world to destruction.
A person who is ignorant and lacks knowledge neither has the power to destroy a land, nor to make it habitable.” In the present time, those people who are leading the world into corruption are the ones who are at the head of the colonializing governments of the world through the guidance of their self-proclaimed “scholars” and “intellectuals”.
Thus, it is clear that true guidance is specifically for those people who have already laid the groundwork (to accept knowledge and further guidance). Based on this, we see that in the past, the true scholars did not give permission to just any student to come and sit in their classes - rather, they tested them in relation to their ethical morals and from this, they would see what level of piety the students were at. However this does not mean that one has the right to hoard his knowledge!
Rather, one must only teach such knowledge to those who are worthy of receiving it and it is through the knowledge that one possesses that he must try to cure the ailments of the people. It does not make a difference if the ailments are in relation to their material life or their spiritual life, although we believe that spiritual ailments and diseases are much worse than the material or physical sicknesses.