وَلَوْ شَآءَ ٱللَّهُ لَجَعَلَكُمْ أُمَّةً وَٰحِدَةً وَلَٰكِن يُضِلُّ مَن يَشَآءُ وَيَهْدِى مَن يَشَآءُ ۚ وَلَتُسْـَٔلُنَّ عَمَّا كُنتُمْ تَعْمَلُونَ

And if Allah please He would certainly make you a single nation, but He causes to err whom He pleases and guides whom He pleases; and most certainly you will be questioned as to what you did.