Originally God should have been as natural to man as our mind is to our body, or as a child relating to his mother. Because man came to have two masters, God divided man in two through the children.
Thus, Unification thought views history as a struggle between Cain, who is in a more dominant position, and Abel, who is in a more subordinate position. Cain type thought and people pursue a more self-centered way. Abel type thought and people pursue a more unselfish God centered way.
As Abel type people form a larger sphere a foundation to receive the Messiah as the original Adam is formed. Centering on these people, chosen by God, heaven is able to build a heavenly kingdom on earth and in the spirit world.