Juel's proposed inclusio comes in chapters 1 and 15 with the terms "Tearing" and "Son of God."
At Jesus' baptism, after he comes out of the water, Mark writes that the heavens were being torn open (σχιζομένους, schizomenous) followed by a proclamation by the voice from heaven that Jesus was the Son of God. Then, in the crucifixion scene, immediately after Jesus breathes his last, the Temple veil was torn in two (ἐσχίσθη, eschisthe) followed by the proclamation by the Centurion that Jesus was the Son of God.
Juel writes the following on the significance of this tearing of both the heavens and the Temple veil:
"What does the tearing mean? It may mean, as interpreted in the Letter to the Hebrews (esp. chapters 9-10), that we now have access to God: We can "have confidence to enter the sanctuary by the blood of Jesus" (Heb. 10:19). Viewed from another perspective, the image may suggest that the protecting barriers are gone and that God, unwilling to be confined to sacred spaces, is on the loose in our own realm. If characters in the story find Jesus' ministry threatening, then they may have good reason. The imagery has enormous power to shape imagination and to open readers to the story. That is, Mark's narrative is about the intrusion of God into a world that has become alien territory -- An intrusion that means both life and death." (Donald Juel, A Master of Surprise, (Minneapolis: Fortress Press, 35-36), 35-36.)I love the thought of summing up the gospel of Mark with the phrase, "God is on the loose."