God is God. He has no obligation to prove His power to anyone. Even at the door of torture and death Jesus refused to ‘put on a show’ for Herod, even though doing so probably would have resulted in His release. However, to an unsaved world, the power of God is measured by the faith and actions of His people. The parting of the Red Sea and destruction of the Egyptian army would not have been heard about in Jericho if the children of Israel had not been in submission to the godly leadership of Moses and began to cross as he instructed them to do.