*

118. O you who believe! Take not as (your) Bitânah (advisors, consultants, protectors, helpers, friends, etc.) those outside your religion (pagans, Jews, Christians, and hypocrites) since they will not fail to do their best to corrupt you. They desire to harm you severely. Hatred has already appeared from their mouths, but what their breasts conceal is far worse. Indeed We have made plain to you the Ayât (proofs, evidences, verses) if you understand.

 119. Lo! You are the ones who love them but they love you not, and you believe in all the Scriptures [i.e. you believe in the Taurât (Torah) and the Injeel (Gospel), while they disbelieve in your Book, the Qur'ân]. And when they meet you, they say, "We believe". But when they are alone, they bite the tips of their fingers at you in rage. Say: "Perish in your rage. Certainly, Allâh knows what is in the breasts (all the secrets)." 

120. If a good befalls you, it grieves them, but if some evil overtakes you, they rejoice at it. But if you remain patient and become Al-Muttaqûn (the pious - see V.2:2), not the least harm will their cunning do to you. Surely, Allâh surrounds all that they do. (Surâh al-Imrân)

The believers are nothing else than brothers (in Islâmic religion). (49:10)