Pretend you're on a jury for a trial over who wrote the Bible: God is suing Satan, because Satan is trying to claim HE wrote the Bible! But the trial hasn't gone like God hoped – Satan has a really good lawyer, and he's making mincemeat of God's case.
First of all, if God wrote the Bible, wouldn't He make everything totally clear, succinct, easy to understand, and unfailingly moral? I mean, He is God, right? Surely God should be a pretty good writer, able to write clearly and concisely.
Instead of beating around the bush about Jesus' divinity, He would just say, "Jesus and I are one and the same." Instead of conflicting messages about marriage, ambiguity about homosexuality, apparent approval of polygamy and slavery, God would have written, "Don't have sex before you're married." "Marriage is only between a man and a woman." "Slavery is a sin." "A man may only have one wife, and a wife only one husband." And so forth. Gosh, it seems pretty easy to me, writing clear, unambiguous commandments!
Just based on poor writing and lack of clarity, it's not looking good for God and His lawyer.
On top of that, there's all that stuff about killing adulterers, expelling a couple from the community if they have sex during a woman's period, requiring a virgin who is raped to marry her rapist, stoning anyone to death who works on the sabbath, and so many more laws that are just plain immoral.
Ladies and gentlemen of the jury, do you really believe that God wrote this stuff about Himself?
Now think about the reverse. What if you were Satan, plotting to do the worst thing you could? You're tired of tempting people into sin — corrupting people one at a time is inefficient. What could you do to amplify your evil? Why not enlist your victims to help you spread evil?
We all know that half-truths are much more dangerous than outright lies, that confusion is much harder to fight than clarity, and that we're all egotistical and want to believe we're better than everyone else.
The best way Satan could get his way would be to write a Bible that was filled with half truths, contradictions, moral ambiguity, appeals to egotism and a "chosen people," and confusing stories that everyone can interpret however they like.
Then, Satan would get his minions to convince the world that this "Bible" was the true word of God. Better yet, Satan would spread the idea that anyone who disagreed would go to Hell (very clever irony, given that he is Satan).
These half truths, contradictions and ambiguities would then start to do their work. People would interpret them differently, and begin to argue, and split into factions. Families would split. Villages would break into religious factions, with bitter hatred for one another. Whole countries would even go to war over this purported "Bible." People would be tortured and murdered when they failed to follow this "Bible," even if they were trying to do their best, just because someone else interpreted the Bible's crazy laws differently.
Satan would laugh with glee. What a wonderful trick he'd pulled!
Better yet, the fear inspired by Satan's Big Lie (about going to Hell if you don't believe) would cause good people to actually defend Satan's own writings! They would start a huge intellectual effort called "Christian apologetics," devoted to explaining why, in spite of the glaring errors, contradictions and immorality in Satan's Bible, it was actually all true, and was in fact the word of Satan's arch-rival, God. This would be Satan's ultimate achievement, that the humans that God created would actually turn against God and defend Satan's Bible!
So, ladies and gentlemen of the jury, what is your opinion? Who wrote the Bible, God, or Satan?