This study sets Jesus' puzzling statement about parable purpose in the context of the epistemology of Jewish apocalyptic literature and of Mark's Gospel as a whole. Apocalyptic motifs in Mark's epistemology include a divinely-willed dualism of revelation and concealment, the association of insight with forgiveness, the mystery of God's dealing with humanity, the penultimate nature of knowledge in the time before the juncture of the ages, and the expectation of a new age of revelation. In Mark, the juncture of the ages occurs at the crucifixion; until then nobody, not even the disciples, can attain full insight.