John Calvin Commentary Joshua 2:10

"For we have heard how Jehovah dried up the water of the Red Sea before you, when ye came out of Egypt; and what ye did unto the two kings of the Amorites, that were beyond the Jordan, unto Sihon and to Og, whom ye utterly destroyed." — Joshua 2:10 (ASV)

For we have heard how, etc. She mentions, as the special cause of consternation, that the widespread rumor of miracles, previously without example, had impressed it on the minds of all that God was warring for the Israelites. For it was impossible to doubt that the way through the Red Sea had been miraculously opened up, as the water would never have changed its nature and become piled up in solid heaps if God, the author of nature, had not so ordered. The transmutation of the element, therefore, plainly showed that God was on the side of the people, to whom he had given a dry passage through the depths of the sea.

The signal victories also gained over Og and Bashan were justly regarded as testimonies of divine favor toward the Israelites. This latter conclusion, indeed, rested only on conjecture, whereas the passage of the sea was a full and indisputable proof, as much so as if God had stretched out his hand from heaven. All minds, therefore, were seized with a conviction that in the expedition of the Israelite people God was the principal leader; hence their terror and consternation. At the same time, it is probable that they were deceived by some vain imagination that the God of Israel had proved superior in the contest to the gods of Egypt; just as the poets depict that every god has taken some nation or other under his protection, wars with others, and that so conflicts take place among the gods themselves while they are protecting their favorites.

But the faith of Rahab takes a higher flight, as she ascribes supreme power and eternity to the God of Israel alone. These are the true attributes of Jehovah. She does not dream, according to the common notion, that some one, out of a crowd of deities, is giving his assistance to the Israelites; but she acknowledges that He whose favor they were known to possess is the true and only God. We see, then, how in a case where all received the same information, she, in the application of it, went far beyond her countrymen.