Hebrews 11:29

"By faith they crossed the Red Sea." In fact, the people who entered into it believed and crossed it as if on dry land. On the other hand, the Egyptians went into it without faith and received the reward for their crimes in the midst of it.

"By faith they passed through the Red Sea." Indeed, they believed that they would pass through, and they did pass through. Such is the power of faith, that it makes possible even those things that are impossible. "but the Egyptians, when they attempted to do the same." For perhaps they suspected that the sea was land, and they also tried to pass through, but their destruction showed that it was truly the sea, and not some kind of illusion. For it was divided beyond its nature for Israel, allowing them to walk on foot; however, it enclosed the Egyptians according to its nature. The purpose, however, was to lead them to believe and hope for the future, and for this reason, he stirred up all this discourse.

"By faith, they passed through the Red Sea as by dry land." Again he compares one whole people with another, lest they should say, we cannot be as the saints. "By faith" (he says) "they passed through the Red Sea, as by dry land, which the Egyptians assaying to do, were drowned." Here he leads them also to a recollection of the sufferings in Egypt. How, "by faith"? Because they had hoped to pass through the sea, and therefore they prayed: or rather it was Moses who prayed. Seest thou that everywhere Faith goes beyond human reasonings, and weakness and lowliness? Seest thou that at the same time they both believed, and feared punishment, both in the blood on the doors, and in the Red Sea? And he made it clear that it was really water, through those that fell into it, and were choked; that it was not a mere appearance: but as in the case of the lions those who were devoured proved the reality of the facts, and in the case of the fiery furnace, those who were burnt; so here also thou seest that the same things become to the one a cause of salvation and glory, and to the other of destruction. So great a good is Faith. And when we fall into perplexity, then are we delivered, even though we come to death itself, even though our condition be desperate. For what else was left for them? They were unarmed, compassed about by the Egyptians and the sea; and they must either be drowned if they fled, or fall into the hands of the Egyptians. But nevertheless He saved them from impossibilities. That which was spread under the one as land, overwhelmed the others as sea. In the former case it forgot its nature: in the latter it even armed itself against them.