جامع الترمذي

An-Numan bin Bashir narrated that the Messenger of Allah (S) said: "The lawful is clear and the unlawful is clear, and between that are matters that are doubtful (not clear); many of the people do not know whether it is lawful or unlawful. So whoever leaves it to protect his religion and his honor, then he will be safe, and whoever falls into something from them, then he soon will have fallen into the unlawful. Just like if someone grazes (his animals) around a sanctuary, he would soon wind up in it. Indeed for every king is a sanctuary (pasture), and indeed Allah's sanctuary is what He made unlawful."