Surah 16

Surah 16:93

"If God had (so) pleased, He would indeed have made you one community, but He leads astray whomever He pleases and guides whomever He pleases. You will indeed be questioned about what you have done."

16.93 – He leads astray whomever He pleases and guides whomever He pleases
In this sūra people are held responsible for their choices, while at the same time other verses seem to say that Allah determines all things (also v. 37).

- from The Quran with Christian Commentary: A Guide to Understanding the Scripture of Islam