And the LORD said to Moses, “Say to Aaron, ‘Stretch out your hand with your staff over the rivers, over the canals and over the pools, and make frogs come up on the land of Egypt!’”
5. And the Lord spake unto Moses, Say unto Aaron. It is questionable whether God thus enjoined Moses in a continuous address, or whether He waited until Pharaoh contumaciously despised His command. It is probable, indeed, that after Pharaoh had paid no attention to the threats, the execution of the punishment was commanded.
Pharaoh is here first threatened and then plagued with frogs, as afterwards, in this chapter, with lice and flies, little despicable inconsiderable animals, and yet by their vast numbers rendered sore plagues to the Egyptians. God could have plagued them with lions, or bears, or wolves, or with vultures or other birds of prey; but he chose to do it by these contemptible instruments. 1.
Commenting on Exodus 8:1-15
And Aaron stretched out his hand over the waters of Egypt,.... That is, towards the waters of the Nile, and towards all places where any water was; for it was not possible he could stretch out his hand over all the waters that were in every place: and the frogs came and covered the land of Egypt: they came up at once, and in such...