Why could only God put the old Adamic nature to death?
The old Adamic nature is spiritual and invisible, beyond human reach. Because people cannot touch or operate in the invisible realm, only God can deal there. Only God could crucify and put the old Adam to death with Christ, just as only God creates the new nature.
Les explains that the old Adamic nature had to be crucified and put to death. This is not a physical matter but a spiritual one, an invisible part of us. Since humans cannot touch the invisible, only God can operate in that realm. Only God could put our old Adam to death in that crucifixion with Christ. By the same principle, only God can give us the new creative personality, the new nature, because it also lies in the invisible area. Thus we are a new work of creation that God alone can do.