I don't think an ass, a cow, or a monkey could have done it. I believe God spoke to Holy people in the past and they wrote of what they heard from God Himself. Was it imagination? Is it imagination when you feel guilt in your heart? Well, listen, it's the voice of conscience speaking to you through your spirit. And who communicates with your spirit to give you direction, to convince you of a mistake? That's right, God!
You think those Holy men wrote dozens of complex books on their own with what they had to deal with back then? Read Psalms 22. It foretells the crucifixion of Jesus Christ about 800 years in advance. Was it imagination? You know it happened 2000 years ago. All prophesies in the past foretold an "old past future" and a "future future". It all depends where in time you are or one was.
These books were later translated from Hebrew into Greek and Aramaic as well. Why would one think that scholars and translators would want to add one more word here, one more word there? What was the need for that? The Bilble is already complex enough. Why make it harder? Why would they think that's what they "thought it meant to say?"
If we observe the Jews, you'll see that they are the most conservative and religious folks on earth. The transcribers, the pharisees and teachers of the law, made sure that every book was translated and copied word for word. The scriptures have been compared and they look the same. I had five different Bibles before. KJV, NKJV, Portuguese Bible by Joao de Almeida, La Biblia de las Americas and a also a French Bible. I have compared several texts from Jesus' words, Book of Malachi, and so on, and the interesting thing is that I found out is that they have one thing in common, they all have the same information, apart from the different languages.