Quran

 11:118

وَلَوْ شَاءَ رَبُّكَ لَجَعَلَ النَّاسَ أُمَّةً وَاحِدَةً ۖ وَلَا يَزَالُونَ مُخْتَلِفِينَ ﴿١١٨﴾

118. Had your Lord willed, He would have made humanity one community, but they will always differ.