﴿ وَلَوْ شَآءَ ٱللَّهُ لَجَعَلَكُمْ أُمَّةًۭ وَٰحِدَةًۭ وَلَٰكِن يُضِلُّ مَن يَشَآءُ وَيَهْدِى مَن يَشَآءُ ۚ وَلَتُسْـَٔلُنَّ عَمَّا كُنتُمْ تَعْمَلُونَ ﴾

“For, had God so willed, He could surely have made you all one single community; however, He lets go astray him that wills [to go astray], and guides aright him that wills [to be guided]; and you will surely be called to account for all that you ever did!”

Please check ayah 16:96 for complete tafsir.