سنن النسائي

An-Nu'man bin Bashir said: "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 which are not as clear. I will strike a parable for you about that: indeed Allah, the Mighty and Sublime, has established a sanctuary, and the sanctuary of Allah is that which He has forbidden. Whoever approaches the sanctuary is bound to transgress upon it, Or he said: 'Whoever grazes around the sanctuary will soon transgress upon it, and whoever indulges in matters that are not clear, he will soon transgress beyond the limits,""