Surah Ash Shura Tafseer

وَلَوْ شَاء اللَّهُ لَجَعَلَهُمْ أُمَّةً وَاحِدَةً

And if Allah had willed, He could have made them one nation,

means, either all following guidance or all following misguidance, but He made them all different, and He guides whomsoever He wills to the truth and He sends astray whomsoever He wills, and He has complete wisdom and perfect proof.

Allah says:

وَلَكِن يُدْخِلُ مَن يَشَاء فِي رَحْمَتِهِ

وَالظَّالِمُونَ مَا لَهُم مِّن وَلِيٍّ وَلَاا نَصِيرٍ

but He admits whom He wills to His mercy. And the wrongdoers will have neither a protector nor a helper.