The Lord spoke to Moses saying:-
“Take the rod, and assemble the people together, you and Aaron your brother, and speak to the rock before them, and it shall yield waters. And when you have brought forth water out of the rock, all the multitude and their cattle shall drink.”
Moses therefore took the rod, which was before the Lord, as he had commanded him, and having gathered together the multitude before the rock, he said to them: “Hear, you 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, and the Lord said to Moses and Aaron: –
“Because you have not believed me, to sanctify me before the children of Israel, you shall not bring these people into the land, which I will give them.”
This is the Water of contradiction, where the children of Israel strove with words against the Lord, and he was sanctified in them.
What did he do wrong? Some rabbis said that he struck the wrong rock – but why would he have done that? Other people suggest that the fault was to strike the rock twice, as if once would have been insufficient. Against this, psalm 105 says that Moses’s fault lay in his speech: he ‘distinguished with his lips’, or ‘he uttered words that were rash’. The double striking with the wood, in fact, represents the Cross, just as the waters that gush forth from the Rock represent the life-giving flow of grace. No, it seems that the fault was to speak as if the outcome were uncertain: not that Moses or Aaron doubted God’s omnipotence, but that they doubted whether He would exercise it on this occasion if favour of a hard-hearted people, when He had said that He would.
This is the second occasion when water springs forth from the rock by means of Moses’s staff. The first occasion was almost forty years before, shortly after the exodus. We can see the two events as representing the two modes under which Christ’s sacrifice exists. First, as the bloody and painful offering of Calvary, by which all graces are earned for mankind; then, the pure and peaceful continuation of the same offering in the Holy Mass, the greatest of the means whereby these graces flow upon the believing soul. In the latter case, there can be fault in the minister, as there was on that occasion with Moses. But nonetheless the waters come forth in great abundance.