Now when they came to Marah, they could not drink the waters of Marah, for they were bitter. Therefore the name of it was called Marah. And the people complained against Moses, saying, “What shall we drink?” So he cried out to the Lord, and the Lord showed him a tree. When he cast it into the waters, the waters were made sweet. (Exodus 15:23-25)
It is the details of some of the Scripture lessons in which one discovers the ‘hidden’ connections and meanings which God has placed in them. In the above excerpt from Exodus, when Moses cries out to God that the Israelites have no water to drink and so are at risk for dying in the desert, God responds. But instead of just providing the Israelites with water, God reveals a tree to Moses. This is an unexpected turn in the story. What kind of tree is revealed to Moses? What kind of ‘tree’ can make unpotable water drinkable?
For early Christian writers, the ‘tree’ which Moses sees is the Cross, or the wood of the Cross. They often used tree and cross interchangeably in their commentaries, certain that God was always revealing Christ throughout the Old Testament. This made an easy connection between the Tree of Knowledge in Paradise by which Eve and Adam sinned against God and the Cross of Christ through whom humanity was saved from sin and death. It is why the above passage from Exodus is part of the Scriptures read for the Feast of the Elevation of the Cross. St Irenaeus of Lyons writes:
And the transgression which occurred through the tree was undone by the obedience of the tree—which [was shown when] the Son of Man, obeying God, was nailed to the tree, destroying the knowledge of evil, and introducing and providing the knowledge of good: and evil is to disobey God, just as to obey God is good. And this is why the word says by the prophet Isaias, foretelling the things that would come to pass – for this reason were they prophets: because they related things to come – so, in this way the Word says by him that, ‘I am not disobedient and do not contradict; I placed my back to the scourging, and my cheeks to the blows, and my face I did not turn from the shame of the spittle’ (Isaiah 50:5-6). So, by means of the obedience by which He obeyed unto death, hanging upon the tree, He undid the old disobedience occasioned by the tree.
And since He is the Word of God Almighty, who invisibly pervades <…> the whole creation, and encompasses its length, breath, height and depth – for by the Word of God everything is administered – so too was the Son of God crucified in these [fourfold dimensions], having been imprinted in the form of the cross in everything; For it was necessary for Him, becoming visible, to make manifest His <form of the cross> <in> everything, that He might demonstrate, by his visible form [on the cross], His activity which is on the invisible level … (ON THE APOSTOLIC PREACHING, p 62)
As we sing of the cross: “Through the Cross joy has come into all the world.” That joy is Jesus Christ. The Tree of the Cross makes the God of love visible to us all.