What did Christian authors of the 7th - 15th centuries say about the Muslim claim of Gospels being direct revelations from God?

According to the Quran, God revealed the Gospels (which it calls Injeel) to Jesus, just like He revealed the Quran to Muhammad, and Torah to Moses, but the New Testament doesn't have any books that can be called God's revelation in the first person to humans. Gospels are biographies that are believed to be written by people inspired by God. My question is did early Christian authors point out this issue? Any references would be very helpful.