A personal experience:
I know more than a hundred converts from Islam to faith in Jesus as their Lord and Savior. Nearly all of them say: When I was still a Muslim, I was constantly in fear of Allah.
This fear is very much woven into the fabric of Islam. It is based on the Qur'an. The reader may come to understand this when reading Trembling for Paradise (found in the second part of the linked article), and following the various other links provided there.