سُوْرَةُ هُوْدٍ

Surah Hud (11) — Ayah 118

Hud · Meccan · Juz 12 · Page 235

وَلَوْ شَآءَ رَبُّكَ لَجَعَلَ ٱلنَّاسَ أُمَّةً وَٰحِدَةً ۖ وَلَا يَزَالُونَ مُخْتَلِفِينَ ﴿118﴾
And if your Lord had so willed, He could surely have made mankind one Ummah [nation or community (following one religion i.e. Islâm)] but they will not cease to disagree.
وَلَوْ walaw And if
شَآءَ shāa your Lord (had) willed
رَبُّكَ rabbuka your Lord (had) willed
لَجَعَلَ lajaʿala surely He (could) have made
ٱلنَّاسَ l-nāsa the mankind
أُمَّةًۭ ummatan one community
وَٰحِدَةًۭ ۖ wāḥidatan one community
وَلَا walā but not
يَزَالُونَ yazālūna they will cease
مُخْتَلِفِينَ mukh'talifīna to differ

Tafsir Taiseer ul-Quran (Facilitation of the Quran) is a comprehensive Quran commentary by Maulana Abdul Rahman Kilani, a renowned Salafi (Ahl al-Hadith) scholar from Pakistan. Known for his eloquent and accessible writing style, Kilani authored this tafsir with a focus on clarity — making Quranic meanings understandable to the common reader. The tafsir provides detailed historical context for verses related to battles and expeditions, and firmly refutes modernist ideologies using strong scriptural evidence. It is widely regarded as an invaluable resource for understanding the Quran and countering deviant interpretations. The tafsir is originally written in Urdu, translated to English by tohed.com.

And if your Lord had willed, He could have made all mankind one community, but they will not cease to differ [131].

[131]
The Real Reason for Disagreement:

Allah Almighty has given man complete freedom to choose between good and evil. If this freedom of choice and will were taken away from man, then disagreement would not be possible, and as long as this freedom exists, people will continue to disagree. Furthermore, if this freedom were taken away from man, the very purpose of his creation would be lost. The paths of good and evil have been made clear to man. Then, for this very purpose, prophets were sent and Allah revealed books. But only a few people made correct use of this freedom of choice and will; most people proved to be wrongdoers who, by choosing the paths of misguidance, made themselves deserving of Hell. This power of will and choice has also been given to the jinn besides humans. Like humans, the majority of jinn have also remained misguided and deserving of Hell.