Claim. Moses was meant to strike the rock at Kadesh-barnea only once — to restore Adam-as-water-giving-rock by indemnity — but in his rage at Israelite faithlessness he struck twice, setting up the condition that when Jesus came as the rock’s fulfillment, Satan could attack his body if the Jewish people lost faith.
Elaboration. The rock symbolized jesus (“the Rock was Christ,” 1 Cor 10:4), and as the root of the tablets it also symbolized God, the origin of Christ. DP layers the typology: perfected Adam should have matured into the water-giving rock; Satan’s strike against unfallen Adam prevented this; God therefore had Moses strike the rock once as indemnity restoration of Adam-as-rock (dp-2-the-providence-of-restoration-under-the-leadership-of-moses §2.2.3).
After the rock yielded water on the first strike, it represented restored Adam — the second Adam, Jesus. Moses’s second strike “in uncontrolled rage” therefore symbolically struck the second Adam. “Moses’ act of striking the rock twice in anger at the faithlessness of the Israelites set up the condition that when Jesus came, if the Jewish people were to turn faithless, Satan would have grounds to confront Jesus, the fulfillment of the rock.”
This sin had two distinguishing properties relative to Moses’s earlier tablet-breaking. First, it could not be undone: while the tablets were external symbols of Jesus (recoverable through Moses’s recarving), the rock was internal — symbolizing God as Christ’s origin — and a strike against the internal cannot be undone externally. Second, it bound Moses to die outside Canaan and gave Satan a lien on his body.
The structural payoff: this is the remote cause of Jesus’s first wilderness temptation (“command these stones to become loaves,” Matt 4:3) — Satan possessed the stone via Moses’s act and meant to keep it. Moses’s mistake is also the structural pre-condition for the cross becoming possible.