In chapters 20 and 21 we have two wonderful types of Christ. In chapter 20 He is pictured as the smitten rock, and in chapter 21 the brazen serpent is a picture of His being offered on the cross as payment for sin. We have already been introduced to the smitten rock type of Christ in Exodus 17:1-7. Throughout the Bible, God is pictured as the Rock; and I Corinthians 10:4 makes it clear that the Rock in Exodus and Numbers is a picture of Christ.
The people could not live without water, nor can we live without the Water of Life (John 4:13,14; 7:37- 39). In the Bible water for drinking is a type of the Holy Spirit, who comes within and satisfies our spiritual thirst. Water for washing is a type of the Word of God, which has cleansing power (John 15:3; Ephesians 5:26).
It would be well to contrast Exodus 17 and Numbers 20. Moses was told to smite the rock in Exodus, and to speak to the rock in Numbers. In Exodus, Moses smote the rock with his rod, and in Numbers he smote it with Aaron's rod. In Exodus, the water was supplied to the people, and in Numbers the water was supplied, but Moses was judged. Christ can only die once. When Moses smote the rock the second time, he was disobeying God and spoiling the type. Furthermore, when he smote it the first time, he used his own rod of divine authority. This pictured Christ smitten with the curse of the law. But Moses was told to use Aaron's rod and to speak to the rock and not smite it. In his disobedience, he exalted himself and failed to glorify God, and was prevented from entering the Promised Land.
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