وَٱلَّذِينَ كَفَرُوا بَعْضُهُمْ أَوْلِيَآءُ بَعْضٍ ۚ إِلَّا تَفْعَلُوهُ تَكُن فِتْنَةٌ فِى ٱلْأَرْضِ وَفَسَادٌ كَبِيرٌ

Wallatheena kafaroo baAAduhumawliyao baAAdin illa tafAAaloohu takunfitnatun fee al-ardi wafasadun kabeer

And those who disbelieved are allies of one another. If you do not do so [i.e., ally yourselves with other believers], there will be fitnah [i.e., disbelief and oppression] on earth and great corruption.