I have been very appreciative of a short work from 1992 by my Doktorvater Stephen C. Barton called The Spirituality of the Gospels. Barton does a lot of thinking and exploring out loud in this book. I found this canonical consideration very interesting.
Mark comes in the canon after Matthew. Perhaps, from the point of view of Christian spirituality, that is appropriate. Read in sequence, we move from a gospel of certainties, evidences, proofs, instructive discourses and Christian casuistry to a gospel where the blinding light of certainty is weaker, the evidences less watertight, the proofs more ‘hermetic’, the discourses more opaque, and the casuistry almost nonexistent. Matthew is more easily digestible–thought still demanding enough!–and provides more supports for those just learning (or relearning) to walk in the spiritual life. Mark, on the other hand, is for those forced by the stormy circumstances of life, and especially the experiences of loss, to find stronger nourishment, stand on their own feet, and walk alongside others who have come that way too. It seems to me not at all surprising, therefore, that whereas Matthew ends with Jesus’ promise of his ever-abiding presence, Mark ends with the absence of Jesus qualified by the mysterious announcement of the messenger that the Risen One ‘goes before’ his followers in Galilee. This absence, this abrupt ending, is disturbing and challenging. It leaves the completion of the story open and lacking in clear definition. It leaves it to be filled out and acted out by every reader and listener prepared to take up the call to follow the Master wherever he leads. (p. 65-66).
Whether or not Barton is right is impossible to know, I think, but he certainly draws out the importance of mystery and “wonder” inspired by Mark.