2 Kings 3:20-22

20About the time for the grain offering the next morning, water suddenly came from the direction of Edom and filled the land.

21All Moab had heard that the kings had come up to fight against them. So all who could bear arms, from the youngest to the oldest, were summoned and took their stand at the border.

22When they got up early in the morning, the sun was shining on the water, and the Moabites saw that the water across from them was red like blood.