Man is afraid, the world is a strange world, and man wants to be secure, safe. In childhood the father protects, the mother protects. But there are many people, millions of them, who never grow beyond their childhoods. They remain stuck somewhere, and they still need a father and a mother. Hence God is called the Father or the Mother. They need a divine Father to protect them; they are not mature enough to be on their own. They need some security.