Genesis 3 is the example you are looking for.
How do these two trees help us to understand the triadic nature of reality and the source of a moral standard?
As we move from creation to the garden, there develops an emerging discontinuity between man and his association with forbidden things. When man is unconstrained by revelation, he quite naturally draws conclusions based upon how he relates to the world around him. Man allows what he experiences to influence how he defines what is relevant. Once man learns to link the natural to the eternal, he learns to represent human events in quite a different way. One cannot build a triadic picture of reality based upon experiential logic. Human rationalization, operating on its own, cannot properly context the relationship of man to the natural world. Building a triadic picture of reality is only possible when one learns to represent human experience in the light of revelation. To do this, one must allow revelation to transcend experiential logic.
There is an example of triadic structure that demonstrates how the natural world and the supernatural world relate to one another in the eternal continuum. At the beginning of man’s history in the garden, the tree of life and the tree of the knowledge of good and evil were mentioned in the context of man’s relationship both to God and to the natural world. The text never seems to indicate that in the beginning there was any prohibition to the tree of life but, that man was only denied access to the tree of knowledge. It was not until after the fall of man that God placed an angel with a flaming sword at the east of the garden to prohibit man’s access to the tree of life.
The way in which Adam chose to represent these trees would reflect his understanding of his association with both God and the natural world. As the narrative unfolds, it becomes clear that access to the tree of life was predicated upon man’s observance of the divine prohibition of the other. Man was to have absolutely no contact with the tree of knowledge. God had provided every tree of the garden for man’s use and pleasure, but this tree was to be left strictly alone. These two trees stand as symbols of a world beyond man’s sensory existence. The tree of forbidden knowledge represents the holiness, the superiority, and the sovereignty of God. It suggests that God always reserves unto Himself the things that belong exclusively to him. It is not merely the tree that has exclusivity, but what that tree represents. As a whole, man is never content to abide by prohibitions. Here, he desires the one thing he is denied. How characteristic this has proven to be of human nature!
Although man was given the highest place of honor as the crowning creation of God, and given dominion over all creation, this tree was a reminder that even man is not God. Man must stand in the index position of this triad and link the tree of knowledge that he can see to the will of God whom he cannot see. He must also link this tree to revealed consequences that he cannot see and has never before experienced. For man to properly relate to both worlds, he must learn to link the eternal world to his world by bringing God’s warning to bear upon his relationship to this tree. He must learn how to define the nature of his relationship to this tree based on what God had told him about it. Now, this epistemology did not just apply to this tree, it extended to everything in man’s dominion. He must understand his relationship to all of his domain based upon this triadic epistemology. God had already defined man’s function in creation and man must relate to his world according to the words of the Lord.
From the beginning, man was confronted with a decision in his association with this icon of good and evil. This tree was a symbol of an unseen reality. There is a particular type of knowledge that man was not equipped to handle and should not seek to obtain. The accessibility of the tree shows that man was given the ability to obtain this knowledge. The prohibition laid down by God says that this knowledge is destructive to man. This reinforces man’s position as a subordinate creature to what is unseen. God had said, “From this tree of the knowledge of good and evil, you shalt not eat of it; for in the day that you eat from it, you shall surely die.” Here is a divine standard given to instruct man on how to think when he considers this tree. Since God has decreed that punishment will follow disobedience, the validity of God’s word is upheld. Divine judgment preserves divine justice because it is through the exercise of justice that God protects his holiness. Observance of this revelation becomes a matter of life and death. The ethics were simple; God said, “Don’t touch it.” This did not require a human analysis of ethics to decide what might be the right thing to do. Contact with the tree was evil both because God said it was evil, and because of what man would suffer as a result.
We know, because of how this tree is interpreted by the physical senses in the text, that man, left on his own, could not arrive at this conclusion. Adam could not see what the tree represented from mere empirical observation. He could only see the physical dynamics of the tree. For the rest, he must rely upon what God had told him about the tree. Man requires instruction from God to protect him from that which he has no point of reference to understand. As the Creator, God understood things about the nature of man and his relationship to his environment that man did not know and was not created to know. Man was not endowed with the capacity to distinguish between good knowledge and evil knowledge. This truth has not changed. The knowledge provided by this tree was not a necessary component for man to fulfill his role within his assigned environment.
The environment of the garden supplied every conceivable human need. He was even given access to the tree of life. The garden was a secure environment where man had no experience with fear, shame, and disgrace. These were yet unknown elements. It was an aesthetic environment where God controlled access to knowledge. There were certain things that man knew by design, but the prohibition of the tree says that there were those things which man should never want to know or seek to know.
In the garden, man enjoyed the presence of God and the full awareness of God. God knew that through disobedience man would be exiled from this controlled and protected environment and from his fellowship with God. By violating God’s prohibition, man challenged the sovereignty of God. Man does not have the authority to mandate a standard of moral conduct. The text of Genesis shows us that this level of knowledge belongs exclusively to God. Because man chose to behave sinfully, he is now confronted with a new reality. Adam is now aware of a particular type of knowledge that will forever change the way mankind represents the relationship he has with the natural world and with his God. It also laid a foundation by which humanity would forever be forced to choose between these two epistemologies. Should we represent reality based on revelation from God or should we rely on those things learned from pragmatic experiences? Which one will we depend upon to tell us the truth about what is relevant?
Now, man has access to the knowledge of good and evil. This presents two problems: First, man does not know the difference between good and evil and secondly, history shows us that when man is left to his own, he will more often than not choose the evil to his own destruction, even when revelation is present. In Genesis 6:5, we see that by the time Noah comes on the scene, “every imagination of the thoughts of the heart is only evil continually,” (RSV). The fact that revelation was available to that generation is evident in the character of Noah. God regarded Noah as “righteous in his generation.” Righteousness is the result of submitting one’s self to revealed constraints. This deterioration of a divinely established ethic shows a complete reversal of a revealed epistemology. This is what happens when the mind of man becomes isolated from the revelation of God. This isolation was willful, deliberate, and fatal. When man is left to himself without a desire for revealed knowledge, he is characteristically self-destructive. If man is to survive spiritually in a cursed environment, it will require a standard that will enable him to represent properly his assigned place within creation.