How Does a Report of Evil Mean The Messenger Is Corrupted?

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Muslims point out that Lot slept with his daughters as a way to show that the "before Scriptures" (Bible) is corrupted. But, where in the Bible, or, the Koran, does it say that if a holy book reports fallible human behavior coming from a prophet, etc., mean that book is not of God/Allah?

I'm posting this video to let you know there is another website to see me on when YouTube deletes all my accounts for exposing Islam.