Okay so it's been a long holy week for me. It all built up to the Easter Vigil mass which was excellent! During the week I thought about something I wanted to post on but subsequently forgot.
I remember. So here it comes!
Back in Eden there were two big important trees: the Tree of the Knowledge of Good and Evil (that's the one Adam and Eve weren't to eat from) and the Tree of Life. Genesis tells us that Adam and Eve were expelled from the Garden so as to not eat from the Tree of Life and live forever. Why's this? Because if they lived forever, they'd live forever in their fallen state! They weren't ready to eat from the Tree of Life...
With the coming of Jesus, the new Adam, humanity gets a second chance! Why do you suppose St. Paul refers to the cross as a tree? It's not necessarily because Jesus was nailed to a tree - but because St. Paul is alluding back to the Garden! Through the cross we have life - but in order to partake of the fruit adorning the Tree of Life we must eat from it.
That's right, we're taken back to the Eucharist. If you want to eat of the Tree of Life, you must eat the body and drink blood of Christ who himself said: "whoever eats my flesh and drinks my blood has eternal life..." (John 6:54).