"The Devil's greatest trick was convincing the world he didn't exist."
We can see that much of The Bible and the Quran is condoning genocide, murder, rape and other atrocities which we now find unacceptable. I wonder if Satan had sneaked some of his own tweaks into a book that used to be perfect in every way. He is supposedly the pinnacle of evil, lies, trickery and deceit so this kinda thing is right up his alley.
If you can convince the world you don't exist, why not take it a little further and try and convince people of the divinity of your message.