Ambrose of Milan : The people of the fathers thirsted, Moses touched the rock, and water flowed out of the rock. Did not grace work a result contrary to nature, so that the rock poured forth water, which by nature it did not contain? — On the Mysteries 9.51 Ambrose of Milan : It does not surpass faith that a virgin gave birth, when we read that even a rock poured out water and that the waves of the sea were made solid in the form of a wall. — Letter 42.7 Caesarius of Arles : Then the Lord said to Moses, "Take the staff and strike the rock, that it may produce water for the people." Behold, there is a rock, and it contains water. However, unless this rock is struck, it does not have any water at all. But when it has been struck, it produces fountains and rivers, as we read in the Gospel: "He who believes in me, from within him there shall flow rivers of living water." When Christ was struck on the cross, he brought forth the fountains of the New Testament. Therefore it was necessary for him to be pierced. If he had not been struck, so that water and blood flowed from his side, the whole world would have perished through suffering thirst for the word of God. — SERMON 103.3