Surah Aal-e-Imran, Verse 118:
يَا أَيُّهَا الَّذِينَ آمَنُوا لَا تَتَّخِذُوا بِطَانَةً مِّن دُونِكُمْ لَا يَأْلُونَكُمْ خَبَالًا وَدُّوا مَا عَنِتُّمْ قَدْ بَدَتِ الْبَغْضَاءُ مِنْ أَفْوَاهِهِمْ وَمَا تُخْفِي صُدُورُهُمْ أَكْبَرُ قَدْ بَيَّنَّا لَكُمُ الْآيَاتِ إِن كُنتُمْ تَعْقِلُونَ
O you who believe! Take not as (your) Bitanah (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 Ayat (proofs, evidences, verses) if you understand.