Claim. Because grown humans cannot literally be reborn through the womb, perfection requires engrafting onto God and True Parents — the messiah comes precisely to provide this engrafting as a substitute for impossible physical rebirth.
Elaboration. SMM gives the theological warrant for why a Messiah-figure (rather than direct individual repentance) is required: ‘In order to reach the point of self-perfection, you must eventually become engrafted to God and True Parents. This engrafting is particularly important given that you are already fully-grown and therefore cannot literally be reborn through the womb. It is for this reason that the Messiah comes’ (Section 5. True Parents’ Love If you have discovered your true, original self, then God is in your heart and you are within the realm of libera- tion. Your original self was born to con- tinue the history of the original lineage through God and True Parents’ original love. Finding this self will resolve every- thing. It is there that True Parents and their love can be found. Since you began from God’s love, when you find yourself, you will discover the two original images of love already planted within you. They are implanted there as the root. You can- not pull yourself out of God nor out of True Parents. Since you are one of their branches, you cannot deny that you have become that branch. For example, if you look at cells, they are all alike, wheth-).
This is a striking exegetical move on Jesus’ Nicodemus discourse (John 3:3–5: ‘you must be born again’). UC reads it not as spiritual regeneration alone but as a recognition that physical rebirth is impossible, therefore a non-biological engrafting mechanism is necessary. The Messiah ‘comes as a man with fully mature, original love – that is, the True Parent’s love. He comes as a representative of the original ideal.’
The arboreal metaphor (branch/root, cellular continuity between leaf and root) supports the doctrine: an engrafted branch genuinely shares the root’s essence — ‘you have all of God’s love and True Parents’ love.’ The mechanism completes itself in the trinity of ‘love, life and lineage’ that resides in the perfected believer.
This is the soteriological underpinning of the blessing sacrament: the Blessing is the engrafting event. It explains why salvation in UC is not transactional-juridical but biological-relational. Evangelical critics typically engage on whether ‘engrafting’ overreads Romans 11’s olive tree metaphor or supplants the Pauline new-creation imagery.
See also. blessing, lineage, messiah-completes-physical-marriage-and-family-salvation