﴿ وَلَوْ شَآءَ ٱللَّهُ لَجَعَلَهُمْ أُمَّةًۭ وَٰحِدَةًۭ وَلَٰكِن يُدْخِلُ مَن يَشَآءُ فِى رَحْمَتِهِۦ ۚ وَٱلظَّٰلِمُونَ مَا لَهُم مِّن وَلِىٍّۢ وَلَا نَصِيرٍ ﴾

“Now had God so willed, He could surely have made them all one single community: none the less, He admits unto His grace him that wills [to be admitted] whereas the evildoers shall have none to protect them and none to succour them [on Judgment Day].”

(Had Allah willed, He could have made them one community) had Allah willed He would have gathered the Jews, Christians and the idolaters in one religion, the religion of Islam, (but Allah bringeth whom He will into His mercy) to His religion: Islam. (And the wrong-doers) the Jews, Christians and idolaters (have no friend) have no relative to assist them (nor helper) to save them from Allah's punishment.