Craig Keener asks the question:
Why would scholars assume that the disciples of Jesus were less reliable transmitters of his teaching than other disciples were for their teachers? If Jesus’ disciples respected him as more than a teacher, rather than less than a teacher, this respect would surely not justify deliberately misrepresenting his teaching.
Read Craig’s very reasonable defense of not treating the Gospels differently than classicists and historians treat every other ancient document.
(H/T: Jim West)