Exodus 8:5

And the Lord spake unto Moses
By a secret impulse upon his mind, for he was now in the presence of Pharaoh, who had refused to let Israel go:

say unto Aaron, stretch forth thy hand with thy rod;
for Aaron carried the rod, and he was the minister of Moses, who was appointed a god to him; and be was to speak and to do whatever he ordered him from the Lord:

over the streams, over the rivers and over the ponds;
the seven streams of the river of Nile, and over the canals cut out of it, and over all places where there was a collection of water for any use for man or beast:

and cause frogs to come up upon the land of Egypt;
out of the streams, rivers, and ponds, immediately.