Mishkat al-Masabih 151
‘A’isha said:
God’s messenger recited, “He it is who has sent down to you the Book in which are fundamental verses” going on to “no one takes warning but those of insight.” 1 She reported God’s messenger as saying, “When you (using the feminine singular pronoun whereas Muslim has the masculine plural) see those who study what is dubious in it, those are they whom God named, so be on your guard against them.” 

(Bukhari and Muslim.) 1 Quran, iii, 7.
وَعَن عَائِشَة قَالَتْ: تَلَا رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ (هُوَ الَّذِي أَنْزَلَ عَلَيْكَ الْكِتَابَ مِنْهُ آيَات محكمات)
وَقَرَأَ إِلَى: (وَمَا يَذَّكَّرُ إِلَّا أُولُو الْأَلْبَابِ)
قَالَتْ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: 
" فَإِذَا رَأَيْتَ وَعِنْدَ مُسْلِمٍ: رَأَيْتُمُ الَّذِينَ يَتَّبِعُونَ مَا تَشَابَهَ مِنْهُ فَأُولَئِكَ الَّذِينَ سَمَّاهُمُ الله فاحذروهم "