I heard Allah's Messenger (may peace be upon himn) as having said this (and Nu'man) pointed towards his ears with his fingers): What is lawful is evident and what is unlawful is evident, and in between them are the things doubtful which many people do not know. So he who guards against doubtful things keeps his religion and honour blameless, and he who indulges in doubtful things indulges in fact in unlawful things, just as a shepherd who pastures his animals round a preserve will soon pasture them in it. Beware, every king has a preserve, and the things God his declaced unlawful are His preserves. Beware, in the body there is a piece of flesh; if it is sound, the whole body is sound and if it is corrupt the whole body is corrupt, and hearken it is the heart.

“I heard the Messenger of Allah (ﷺ) say: ‘That which is lawful is plain and that which is unlawful is plain, and between them are matters that are not clear, about which not many people know. Thus he who guards against the unclear matters, he clears himself with regard to his religion and his honor. But he who falls into the unclear matters, he falls into that which is unlawful. Like the shepherd who pastures around a sanctuary, all but grazing therein. Every king has a sanctuary. And beware! Allah’s sanctuary is His prohibitions. Beware! In the body there is a piece of flesh which, if it is sound, the whole body will be sound, and if it is corrupt, the whole body will be corrupt. It is the heart.’”

‘Know that a man who relates everything he hears is not safe, and he can never be an Imām, as long as he narrates everything he hears’.