And if Allah willed, He could have made them [of] one religion, but He admits whom He wills into His mercy. And the wrongdoers have not any protector or helper.
The Saheeh International Quran Translation
وَلَوْ شَآءَ ٱللَّهُ لَجَعَلَهُمْ أُمَّةً وَٰحِدَةً وَلَٰكِن يُدْخِلُ مَن يَشَآءُ فِى رَحْمَتِهِۦ وَٱلظَّٰلِمُونَ مَا لَهُم مِّن وَلِىٍّ وَلَا نَصِيرٍAnd if Allah willed, He could have made them [of] one religion, but He admits whom He wills into His mercy. And the wrongdoers have not any protector or helper.