Regarding the tree of the trees in Eden, the question we need to ask is: what does it mean to be the tree of the knowledge of good and evil? The Law does not disclose Evil, so this is an insufficient parallel for those who might suggest that one tree is grace and the other tree is the law! Where did this tree come from? Did God plant it, or did He plant the garden around where this tree was located?
Trees are a pervasive metaphor in scripture and in one sense; we are all trees to God, as he requires us to be fruitful. There are good trees in scripture and bad trees. The four good trees in the Bible are: the palm tree (imagery of an oasis in the desert, and a symbol for worship), the olive tree (anointing oil – symbolic of the Holy Spirit), a blossoming almond tree (pictured on the temple veil representing the tree of life), and the hyssop plant (representing healing, and the closest image we have in scripture of the tree of life).
Other than the trees that seemed to cast a dark shadow on King Saul’s life, the only consistently evil tree in scripture seems to be an evergreen. The Israelites would place their idols under these trees and sacrifice to them there. The king of all these evergreens was the Great Cedar mentioned in Ezekiel 31 – both a metaphor for Satan, and the tree of the knowledge of good and evil. But how can the cedar be analogous to the tree of the knowledge of good and evil when it doesn’t bear any fruit?
The fruit of the great cedar is idolatry, as it is the tree that will not rot (Isaiah 40:20). So this tree of knowledge of good and evil has something to do with Satan, and idolatry. Satan fell because he found another to worship – in Lucifer’s case it was himself. So the knowledge of good and evil is to know God, and yet to worship another. Satan fell because having known God, she turned from God. Adam and Eve fell because having known God, they chose to turn from God. We get to be the bride of Christ because having known evil, we choose Christ.