According to sources I've come across, Cecil Be DeMille also used a lot of the material from the Koran. You may not be aware that of all the Prophets mentioned in the Koran, he gets the most mentioned, including stories or narratives that are not in the Bible like the chase given by the Pharoah and drowning. Cecil Be De Mille went to Palestine and saw firsthand trouble brewing between Jews and Arabs and so decided to bring the two together in the making of this film and got the actors, the scriptwriter and the crews and everybody on the set to read and get acquainted with Koran, which was unheard of in those days and the scriptwriter ended up being a huge fan. A lot of dialogues in the script were inspired or taken from the Koran.