I’ve become increasingly convinced that the search for authentic words of Jesus is a waste of time. The human memory has been studied exhaustively in recent decades, and the overriding picture which emerges is one of fragility and subjectivity. On an individual level, we tend to fill in the blanks, to make sense of what we see or hear, and to allow later information to blend into and inform what we think we remember. Over time, we may retain the gist of what happened, but not the specific details….the idea that a person or a group could remember and transmit Jesus’ sayings perfectly seems highly unlikely.
Dr. Bond has a good article on the subject – go read it.