It is nothing about Islam. It is a 1936 film with Marlene Dietrich. It is about two people finding themselves. One is Dietrich, a devout Catholic, the other is a Trappist monk who has lost his faith and run away.
It gives an insight into spirituality of duty and the power of vows that we seem to have lost. It doesn't quite end happily but it does show the power of sacrificial love and self denial and placing God first.