﴿ وَلَوْ شَآءَ رَبُّكَ لَجَعَلَ ٱلنَّاسَ أُمَّةًۭ وَٰحِدَةًۭ ۖ وَلَا يَزَالُونَ مُخْتَلِفِينَ ﴾

“And had thy Sustainer so willed, He could surely have made all mankind one single community: but [He willed it otherwise, and so] they continue to hold divergent views'”

Please check ayah 11:119 for complete tafsir.