Book 15 gives God’s liberation a concrete shape. God is liberated as the true family lost in Eden is restored through True Parents.
That means liberation is not only emotional consolation or abstract victory over evil. It is the historical recovery of family, lineage, and peoplehood under God’s love.
This makes the doctrine easier to preach clearly. God’s sorrow is healed not by admiration alone, but by the recovery of the household He intended from the beginning.