حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ الأَعْلَى الصَّنْعَانِيُّ، قَالَ حَدَّثَنَا خَالِدٌ، - وَهُوَ ابْنُ الْحَارِثِ - قَالَ حَدَّثَنَا ابْنُ عَوْنٍ، عَنِ الشَّعْبِيِّ، قَالَ سَمِعْتُ النُّعْمَانَ بْنَ بَشِيرٍ، قَالَ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم - فَوَاللَّهِ لاَ أَسْمَعُ بَعْدَهُ أَحَدًا يَقُولُ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم - يَقُولُ ‏"‏ إِنَّ الْحَلاَلَ بَيِّنٌ وَإِنَّ الْحَرَامَ بَيِّنٌ وَإِنَّ بَيْنَ ذَلِكَ أُمُورًا مُشْتَبِهَاتٍ ‏"‏ ‏.‏ وَرُبَّمَا قَالَ ‏"‏ وَإِنَّ بَيْنَ ذَلِكَ أُمُورًا مُشْتَبِهَةً ‏"‏ ‏.‏ قَالَ ‏"‏ وَسَأَضْرِبُ لَكُمْ فِي ذَلِكَ مَثَلاً إِنَّ اللَّهَ عَزَّ وَجَلَّ حَمَى حِمًى وَإِنَّ حِمَى اللَّهِ عَزَّ وَجَلَّ مَا حَرَّمَ وَإِنَّهُ مَنْ يَرْتَعْ حَوْلَ الْحِمَى يُوشِكْ أَنْ يُخَالِطَ الْحِمَى ‏"‏ ‏.‏ وَرُبَّمَا قَالَ ‏"‏ إِنَّهُ مَنْ يَرْعَى حَوْلَ الْحِمَى يُوشِكْ أَنْ يَرْتَعَ فِيهِ وَإِنَّ مَنْ يُخَالِطِ الرِّيبَةَ يُوشِكْ أَنْ يَجْسُرَ ‏"‏ ‏.‏

An-Nu'man bin Bashir said: "I heard the Messenger of Allah 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,"" Translation Not Available

Book Ref: Sunan An Nisai Book 44 Hadith 4453
Web Ref:  Sunan An Nisai Vol 5 Book 44 Hadith 4458