Hud 11:118 ولو شاء ربك لجعل الناس امة واحدة ولا يزالون مختلفين ١١٨
وَلَوۡ
شَآءَ
رَبُّكَ
لَجَعَلَ
ٱلنَّاسَ
أُمَّةٗ
وَٰحِدَةٗۖ
وَلَا
يَزَالُونَ
مُخۡتَلِفِينَ
١١٨
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.
Read Tafsir
Ibn Kathir (Abridged)
Allah has not made Faith universally accepted
Allah, the Exalted, informs that He is able to make all of mankind one nation upon belief, or disbelief. This is just as He said,
وَلَوْ شَآءَ رَبُّكَ لآمَنَ مَن فِى الاٌّرْضِ كُلُّهُمْ جَمِيعًا
(And had your Lord willed, those on earth would have believed,
…Allah has not made Faith universally accepted
Allah, the Exalted, informs that He is able to make all of mankind one nation upon belief, or disbelief.
…