2 Kings 3:20-22

20The next morning, about the time of offering the sacrifice, behold, water came from the direction of Edom, till the country was filled with water.

21When all the Moabites heard that the kings had come up to fight against them, all who were able to put on armor, from the youngest to the oldest, were called out and were drawn up at the border.

22And when they rose early in the morning and the sun shone on the water, the Moabites saw the water opposite them as red as blood.