An-Nahl 16:93

Walaw shaa Allahu lajaAAalakumommatan wahidatan walakin yudillu man yashaowayahdee man yashao walatus-alunna AAamma kuntumtaAAmaloon

And if Allāh had willed, He could have made you [of] one religion, but He sends astray whom He wills and guides whom He wills. And you will surely be questioned about what you used to do.

If Allah so willed, He would have made all of you a single community, but He lets whom He wills go astray and takes whom He wills to the right path; and surely you will be questioned about what you used to do.