The Bible records that Moses was sent by God into Egypt to lead the Israelites out, and that in obedience to this commission Moses went to Egypt and promised the Israelites deliverance. That deliverance was effected, but not by the exercise of any power which Moses or the Israelites possessed. In the supreme moment it was effected by powers of Nature, which lie beyond human control. This story hangs together as a consistent whole. If Moses was genuinely commissioned and inspired by God, and the promise of deliverance came from God and if its fulfillment was effected by God, all would be intelligible. But as soon as we begin to discard any of these elements, we find ourselves in difficulties. If Moses was not really called by God, but merely fancied himself to be so called, we are left without any explanation of the fulfillment of his promise. If they arose from nothing deeper than his own wishes and dreams, there lay here no power to set in motion the forces of Nature for their fulfillment. If, on the other hand, we suppose that it was by a fortunate coincidence that the forces of Nature effected the deliverance, we are left without any explanation of the prior confidence of Moses and the promise of deliverance which he brought. To distribute the elements of the story amongst self-deception and chance is to offer no explanation; to find the hand of God in it is to find a simple and sufficient explanation.
from pages 10- 11, The Unity of the Bible