2 Reyes 3:22

22. Saw the water… red as blood “As the suddenly appearing mass of waters was effected in a natural way by a violent rain in the distance, so also the illusion, that was so fatal to the Moabites, is explained in a natural way, indicated even in the text. From the red earth of the pits the water collected in them had assumed a reddish colour, which was considerably increased by the rays of the rising sun falling upon it, so that, seen from the distance, it must have appeared like blood. But the Moabites might be the less disposed to think of an optical illusion, as by their familiar acquaintance with the region they knew that the wady had at that time no water, and they had seen or learned nothing of the rain which had fallen far from them in the Edomite mountains.” Keil.