Shall lothe - The water of the Nile has always been regarded by the Egyptians as a blessing unique to their land. It is the only pure and wholesome water in their country, since the water in wells and cisterns is unwholesome, while rain water seldom falls, and fountains are extremely rare.
Related Commentaries of Exodus 7:18
Exodus 7:18
18 And the fish that is in the river shall die, and the river shall stink; and the Egyptians shall lothe to drink of the water of the river.