Rock

And all drank the same spiritual drink. For they drank of that spiritual Rock that followed them, and that Rock was Christ.
1 Corinthians 10:4

Since the verse above is pulled out of context, it’s a little difficult to understand what it is talking about. The Apostle Paul was making a reference to the Old Testament story of Moses getting water from the rock. Actually, the miracle was performed on many occasions.

Rocks by nature aren’t very absorbent. There is no such thing as a soggy rock. Also a huge amount of water would be needed. Do the math. Most scholars agree that the Israelites numbered around 3 million people and probably had hundreds of thousands of heads of  livestock. They’d need at least 200,000 gallons of water per hour, 24-7 calculating a gallon of water per day per person with two gallons per day per animal, and that's not allowing for baths, washing clothes or spillage. Even if they got  that much water, it would have to be rationed.

In reality, the water coming out of the rock would have to be a small river that would constantly flow and allow for water seeping into desert sand. Once they found this kind of water source, they wouldn’t find another. But, they did leave it and then found another water-producing rock and then another and then another.

If the desert was full of these "gusher-rocks" then it wouldn’t be a desert. Truth is that God was performing a daily (hourly) miracle to provide His people with water and this miracle followed them as they wandered the wilderness for forty years. In the verse above, Paul tells us that it was actually Christ in His capacity of Creator that was producing the H₂O out of stone. It was the Second Person of the Trinity come down from heaven to follow His people and provide what they needed to live. This time He manifested Himself as the Rock.