Commander of the Faithful (AS) said: With the exception of the centers of knowledge, the world is nothing but ignorance. The knowledge in its entirety is evidence against the ones who know and fail to practice. If they practice what they know for the sake of showing off, they shall be held accountable. They shall not be held accountable for what they practiced with sincerity. The path of sincerity is a dangerous one. Hence, the Servant of Allah should beware.