Quran 4:91

Surah An-Nisa, verse - 91
You will find others desiring to have security from you, by manifesting belief before you, and security from their own people, through unbelief, when they return to them, and these were [the tribes of] Asad and Ghatafān; yet whenever they are returned to sedition, [whenever] they are summoned to idolatry, they are overwhelmed by it, falling into it in the worst of ways. So, if they do not stay away from you, by refraining from fighting you, and, do not, offer you peace, and, do not, restrain their hands, from you, then take them, as captives, and slay them wherever you come upon them, [wherever] you find them; against them We have given you clear warrant, a clear and manifest proof for you to slay them and capture them, on account of their treachery.
मदीनए तैय्यिबह में असद और ग़तफ़ान क़बीले के लोग दिखावे के लिये इस्लाम का कलिमा पढ़ते और अपने आप को मुसलमान ज़ाहिर करते और जब उनमें से कोई अपनी क़ौम से मिलता और वो लोग उनसे कहते कि तुम किस चीज़ पर ईमान लाए तो वो लोग कहते कि बन्दरों बिच्छुओं वग़ैरह पर. इस अन्दाज़ से उनका मतलब यह था कि दोनों मुनाफ़िक़ थे. उनके बारे में यह आयत उतरी.