For, had God so willed, He could surely have made you all one single community; however, He lets go astray him that wills [to go astray], and guides aright him that wills [to be guided]; and you will surely be called to account for all that you ever did!
An-Nahl : 128
وَلَوْ شَاءَ اللَّهُ لَجَعَلَكُمْ أُمَّةً وَاحِدَةً وَلَٰكِنْ يُضِلُّ مَنْ يَشَاءُ وَيَهْدِي مَنْ يَشَاءُ ۚ وَلَتُسْأَلُنَّ عَمَّا كُنْتُمْ تَعْمَلُونَ