Through sin, human nature represented by the first humans, lost its honor–it’s original perfection and graced elevation. It is raised up anew in every individual human soul that is reborn through the grace of baptism into the state of the children of God. It is crowned in the chosen souls who attain to bridal union with the Redeemer. This happens “under the tree of the cross”, as the ripened fruit of the death of the cross and in co-suffering this death on the cross.
But how are we to understand that the place of this elevation and that of the fall are one and the same place, the tree of the cross and the tree of paradise, one and the same? It seems to me the solution lies in the mystery of sin. The tree in the paradise, the fruits of which were forbidden to human beings, was, after all, the tree of knowledge of good and evil. Human beings could only get an authentic experimental knowledge of evil and its radical opposition to good by doing evil. So we may see in the tree of paradise and emblem for human nature in its openness to sin and in the fruit of the tree, actual sin (the first as well as every succeeding one) with all its consequences. But the most terrible result of sin, and therefore the revelation of its terrifying effectiveness is the passion and death of Christ.
St. Edith Stein, The Science of the Cross