The Age of Grace had dawned, but mankind was still not ready for it. As great and awesome and wonderful as the Crucifixion was, it only concluded God’s purpose for the previous time period (Age of Law): It didn’t start something new. It wasn’t until the Resurrection that the Tree of Life was made available again to any who were without sin (all sins were paid for, even those not yet committed). It was this Tree, Jesus, which changed the very nature of man, making him a new creature, not a re-newed one.

[excerpted from "Practical Christianity"]