"It must needs be that there is an opposition in all things. If it were not so...all things must needs be a compound in one: wherefore if it should be one body it must needs remain as dead, having neither life nor death."
"For he is our peace, who hath made both one, and hath broken down the middle wall of parturition between us...for to make in himself of twain one new man, so making peace...From whom the whole body fitly joined together, according to the effectual working in the measure of every part, maketh increase of the body unto the edifying of itself in love."
Lehi and Paul both speak of the idea of "one body," but while Lehi's vision is of an undead zombie-like being, Paul praises the peace and perfection, the edification in love. Why are they so different?
Originally, we are one body but to stay that way is a dead end. This is the body Lehi speaks of, our premortal formlessness where we are everything and nothing, where light and dark mush together and all is fuzzy. The endless, unified ocean of precreation. We must break free from this infantile urobouros and enter the world of opposition in order to come to know ourselves and to grow.
In this world of opposition that Lehi sketches, everything is fragmented and alienated. We are broken to bits by this world, divided from God, from others, from ourselves. It is a painful process, but it's through this that we come to know who we are, who we were, to discover all that was undifferentiated in us before and bring it to light. We go through life and come upon moments of recognition, when we realize that we've discovered something that we never knew was lost until we found it. People, places, art, music, poems, animals, anything can trigger these startling recognitions, and give us a glimpse of a piece of ourselves.
And so we wander through the world, gathering ourselves back together, like Egyptian Isis painstakingly gathering up the body parts of her dismembered husband. And as we piece these fragments back together we become whole again, a whole body, the twain made one. This is the redeemed body that Paul speaks of. We restore the original unity, not through a regression into comforting oblivion, but through the active union of the parts of ourselves we have discovered and reorganized. William Blake called it Organized Innocence--the edenic, golden innocence of infancy is lost to us forever, and for good reason. The new Innocence is achieved through gathering, loving, recognizing, seeking, organizing, creating.
The life-in-death and death-in-life body of Lehi is our unsustainable past; the reintegrated, self-aware Body of Paul is our possibility.