The ancient and saintly fathers and theologians have contrasted the living wood with dead and have allegorized that contrast this way: From the living wood came sin and death; from the dead wood, righteousness and life. They conclude: do not eat from that living tree, or you will die, but eat of the dead tree; otherwise you will remain in death.
You do indeed desire to eat and enjoy [the fruit] of some tree. I will direct you to a tree so full you can never eat it bare. But just as it was difficult to stay away from that living tree, so it is difficult to enjoy eating from the dead tree. The first was the image of life, delight, and goodness, while the other is the image of death, suffering and sorrow because one tree is living, the other dead. There is in man’s heart the deeply rooted desire to seek life where there is certain death and to flee from death where one has the sure source of life.
–Martin Luther, “That a Christian Should Bear his Cross With Patience,” 1530