So do we read in Former Pope Benedict XVI’s The Spirit of the Liturgy (2000 Ignatius Press). And we thank The Adoremus Bulletin (February 2012), sent from St. Louis Missouri, for providing this excerpt.
The Fathers belonging to the Greek cultural world were more directly affected by another discovery. In the writings of Plato, they found the remarkable idea of a cross inscribed upon the cosmos (cf Timaeus 34ab and 36bc). Plato took this from the Pythagorean tradition, which in its turn had a connection with the traditions of the ancient East.
First, there is an astronomical statement about the two great movements of the stars with which ancient astronomy was familiar: the ecliptic (the great circle in the heavens along which the sun appears to run its course) and the orbit of the earth. These two intersect and form together the Greek letter Chi, which is written in the form of a cross (like an X).
The sign of the cross is inscribed upon the whole cosmos. Plato, again following more ancient traditions, connected this with the image of the deity: the Demiurge (the fashioner of the world) "stretched out" the world soul "throughout the whole universe".
Saint Justin Martyr (d. ca. 165), the Palestinian-born first philosopher among the Fathers, came across this Platonic text and did not hesitate to link it with the doctrine of the triune God and His action in salvation history in the person of Jesus Christ. He sees the idea of the Demiurge and the world soul as premonitions of the mystery of the Father and the Son - premonitions that are in need of correction and yet also capable of correction. What Plato says about the world soul seems to him to refer to the coming of the Logos, the Son of God. And so he can now say that the shape of the cross is the greatest symbol of the lordship of the Logos, without which nothing in creation holds together (cf I Apo1. 55).
The Cross of Golgotha is foreshadowed in the structure of the universe itself. The instrument of torment on which the Lord died is written into the structure of the universe. The cosmos speaks to us of the Cross, and the Cross solves for us the enigma of the cosmos. It is the real key to all reality. History and cosmos belong together. When we open our eyes, we can read the message of Christ in the language of the universe, and conversely, Christ grants us understanding of the message of creation.
From Justin onward, this "prophecy of the Cross" in Plato, together with the connection of cosmos and history that it reveals, was one of the fundamental ideas in patristic theology. It must have been an overwhelming discovery for the Fathers to find that the philosopher who summed up and interpreted the most ancient traditions had spoken of the cross as a seal imprinted on the universe.
Saint Irenaeus of Lyons (d. ca. 200), the real founder of systematic theology in its Catholic form, says in his work of apologetics, the Demonstration of the Apostolic Preaching, that the Crucified One is "the very Word of Almighty God, who penetrates our universe by an invisible presence. And for this reason He embraces the whole world, its breadth and length, its height and depth, for through the Word of God all things are guided into order. And the Son of God is crucified in them, since, in the form of the Cross, He is imprinted upon all things" (I, 3).
This text of the great Father of the Church conceals a biblical quotation that is of great importance for the biblical theology of the Cross. The epistle to the Ephesians exhorts us to be rooted and grounded in love, so that, together with all the saints, we "may have power to comprehend with all the saints what is the breadth and length and height and depth, and to know the love of Christ which surpasses knowledge" (3:18f).
There can be little doubt that this epistle emanating from the school of Saint Paul is referring to the cosmic Cross and thereby taking up traditions about the cross-shaped tree of the world that holds everything together-- a religious idea that was also well known in India.
Saint Augustine has a wonderful interpretation of this important passage from Saint Paul. He sees it as representing the dimensions of human life and as referring to the form of the crucified Christ, whose arms embrace the world and whose path reaches down into the abyss of the underworld and up to the very height of God Himself (cf De doctrina christiana 2,41, 62; Corpus Christianorum 32,75f).
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The Eastern Orthodox Church has traditionally understood the tree of life in Genesis as a prefiguration of the Cross, which humanity could not partake of until after the incarnation, death and resurrection of Jesus.
One of the hymns chanted during the forefeast of the nativity of Christ says:
“Make ready, O Bethlehem, for Eden hath been opened for all. Prepare, O Ephratha, for the tree of life hath blossomed forth in the cave from the Virgin; for her womb did appear as a spiritual paradise in which is planted the divine Plant, whereof eating we shall live and not die as did Adam. Christ shall be born, raising the image that fell of old”.
The cross of Christ is also referred to as the tree of life, and in the service books, Jesus is sometimes likened to a "divine cluster" of grapes hanging on the "Tree of the Cross" from which all partake in Holy Communion.
This theme is also found in Western Christianity. By way of an archetypal example consider Bonaventure's "biography" of the second person of the Trinity, entitled "The Tree of Life." [see Cousins, The Classics of Western Spirituality Series] ….