There was a cycle of spiritual meditation during the minority of the world's life, and when it came to full age that was the period of the coming of Muhammed. For all who came before -- Abraham, Moses, Christ -- promised the world that someone else would come, as the guardian of a child would say, "I have to go, but another guardian will be appointed," for the child was yet a minor. By Muhammed's plain declaration of the sacred statement, la illaha illa 'llah hu, "none exists save God," he entrusts the world with the knowledge of unity which so far was constantly and gradually being uncovered step by step. It was by the declaration unveiled fully. This is what is meant by the seal of prophecy, that after this culmination there begins the new era when the spiritual government so established hitherto may work without an open claim, and teachers may advise as an adviser, not as a guardian or a mediator.