The Struck Rock and the Pierced Side
Old Testament: Numbers 20:10-11
And having gathered together the multitude before the rock, he said to them: Hear, ye rebellious and incredulous: Can we bring you forth water out of this rock? And when Moses had lifted up his hand, and struck the rock twice with the rod, there came forth water in great abundance, so that the people and their cattle drank.
New Testament: 1 Corinthians 10:4; John 19:34
And all drank the same spiritual drink; (and they drank of the spiritual rock that followed them, and the rock was Christ.) ... But one of the soldiers with a spear opened his side, and immediately there came out blood and water.
The connection
Paul does not merely compare the wilderness rock to Christ; he identifies it outright: "they drank of the spiritual rock that followed them, and the rock was Christ" (1 Corinthians 10:4). Moses struck the rock twice in disobedient anger, though God had only told him to speak to it, and water poured out anyway in abundance for a people who had done nothing to deserve it. At the Cross, the true Rock is struck once, finally, and does not need to be struck again. When the soldier's spear opens His side, "immediately there came out blood and water" (John 19:34), the two sacraments the Church has always read there, Baptism and the Eucharist, flowing from the same wound. What Moses' rod released for a day, and only after the people clamoured for it, the spear releases forever, and without anyone having asked for it.
Moral sense
The Israelites had to be given water again and again through the whole wilderness journey, and their complaining led even Moses himself into disobedience. The wound in Christ's side needs no repeating and asks nothing but to be approached: not another blow, only thirst, and the willingness to come and drink from what is already flowing.
Anagogical sense
The blood and water that flowed once from a wound will not stop flowing: John sees it again at the very end, no longer confined to a single moment on a single afternoon, but "a river of water of life, clear as crystal, proceeding from the throne of God and of the Lamb" (Apocalypse 22:1), the same spring finally shown for what it always was.
Warrant
Checked in the Greek: petra is the same noun at Numbers 20:10-11 in the Septuagint and at 1 Corinthians 10:4, where Paul names the rock outright, and hydor runs from Numbers 20:10-11 to the water of John 19:34.
Catechism of the Catholic Church, paragraph 1225.
The verses
Numbers 20:10 · Numbers 20:11 · 1 Corinthians 10:4 · John 19:34
