As Israel wondered through the wilderness those forty years God always provided their necessities. They were not always happy with the menu, but God was faithful. Interestingly, there were two special cases in which God provided them water from a rock. On the first occasion He instructed Moses to smite the rock and he obeyed (Ex 17:6). However, on the second occasion his instructions were to speak to the rock (Num 20:8). Instead, Moses smote the rock as he had before. He disobeyed God and lost his passage into the Promised Land. While this was certainly discouraging for Moses, he may not have realized the significance of the rock he had smitten. The apostle Paul told the church at Corinth that this rock was Christ (1 Cor 10:4).
In the omniscient mind of God, He used this rock as a shadow of His Son. Just as the rock was smitten unjustly so was the Son of God (Matt 26:67). That smitten rock brought forth water abundantly for the people. Christ taught that He was the water of life (Rev 21:6). Furthermore, Israel had to make the decision and effort to drink the water presented before them. For those who desire to drink of Christ’s water today, they must decide to drink of it as well. Another consideration would be the point in which the water flowed. There was no water for Israel until it was smitten. Although Christ was on Earth in the flesh, salvation was not available until He was smitten likewise. Considering these comparisons certainly explains why Paul would describe that rock as Christ. Christ is the Rock of Ages who was smitten for the salvation of all who will accept it.