Did God really write the Bible?
Yes … yes he did.
Here is what happened. “When the Lord finished speaking to Moses on Mount Sinai, he gave Moses the two tablets of the covenant law, the tablets of stone inscribed by the finger of God.” Deuteronomy 9:10
So God wrote the first set of commands.
But when Moses came off the mountain and saw the people partying and worshiping a golden calf, he became angry, threw down the tablets and broke them. Which meant he had to start over. [This was waaaay before control-S and files saved in the Cloud]. Back up the mountain he went.
The Lord said to Moses, “Chisel out two stone tablets like the first ones, and I will write on them the words that were on the first tablets, which you broke. So Moses chiseled out two stone tablets like the first ones and went up Mount Sinai early in the morning, as the Lord had commanded him; and he carried the two stone tablets in his hands. Then the Lord came down in the cloud and stood there with him and proclaimed his name, the Lord. And he passed in front of Moses, proclaiming … Exodus 34:1-5
There is a long section where God recites the commands to Moses and then …
The Lord said to Moses, “Write down these words, for in accordance with these words I have made a covenant with you and with Israel.” Moses was there with the Lord forty days and forty nights without eating bread or drinking water. [I hear writers can behave this way when they’re on a deadline.] And he wrote on the tablets the words of the covenant—the Ten Commandments. Exodus 34:27-28
Afterward all the Israelites came near him, and he gave them all the commands the Lord had given him on Mount Sinai. Exodus 34:32
So God wrote the first set of ten commandments and it appears he dictated the second set to Moses, along with all the other commands.
Of course there is much more to the Bible than just his commands. But God wrote the first draft of the first section.