I just finished and added to the Christian Cadre site a new article related to Paul's knowledge of the historical Jesus: Paul's Knowledge of the Garden of Gethsemane Narrative.
From the conclusion:
The evidence that Paul and Mark's narrative of the Garden of Gethsemane are referring to the same event is strong. Both authors are referring to an older, preexisting tradition. The distinctiveness of the phrase, "Abba Father" is so unique that its usage by Paul and Mark is almost certainly not a coincidence. That Paul's reference to the phrase has Jesus’ own crying out to God in mind as its origin is reinforced by the context in which he employs the phrase. The very ability to cry out "Abba Father" is a sign of becoming an adoptive Son of God as Jesus was the Son of God. Not only that, but it is the very Spirit of Jesus that enables us to cry out to God on such a familiar level. The earthly location of Jesus' use of "Abba Father" is attested by Galatians' describing the event just after stating "God sent his Son, Born under the Law, Born of a Woman." Romans associates the scene with Jesus' time of suffering before his resurrection, which certainly fits the Garden of Gethsemane scene.
A number of consequences follow from the strong likelihood that Paul is referring to Jesus’ prayer at the Garden of Gethsemane which is narrated in the Gospel of Mark. First, it provides additional evidence for the authenticity of the Garden of Gethsemane tradition and, with it, the idea that Jesus prayed using a unique form of address stressing his special status with God. Second, it provides yet another detail from the life of Jesus to which Paul refers, further damaging the notion that Paul had no interest in the life of Jesus. Third, the nature of the reference is instructive in that though Paul refers to the life of Jesus he does not do so by repeating the entire narrative. This lends support to the view that Paul’s purported “silence” about the life of Jesus is due to the fact that “he takes knowledge of Jesus’ teaching for granted. . . . Paul did not need to quote from it often because he and his readers have been taught it and know it well.” Wenham, op. cit., page 5. Because Paul had already passed on the narrative of the Garden of Gethsemane to the church in Galatia, he could make a point using the episode and the call to God as “Abba Father” without repeating the entire story. Perhaps more significant is that Paul can assume the Christians in Rome – where he had not founded a church – were just as familiar with the Garden of Gethsemane narrative. If that is true with this story from Jesus’ life, it is most likely true of other “echoes” of Jesus’ life and teachings that can be found throughout Paul’s letters.
Check it out and let me know what you think.