"Verily, the lawful is clear and the unlawful is clear, and between the two of them are doubtful matters about which many people do not know. Thus, he who avoids doubtful matters clears himself in regard to his religion and his honor, and he who falls into doubtful matters will fall into the unlawful as the shepherd who pastures near a sanctuary, all but grazing therein. Verily, every king has a sanctum and the sanctum of Allah is his prohibitions. Verily, in the body is a piece of flesh which, if sound, the entire body is sound, and if corrupt, the entire body is corrupt. Truly, it is the heart. "