The Midrash (Tanchuma Bo, Siman 4) explains that the plagues came upon the Egyptians like a king who wants to conquer a country and subdue its inhabitants to his will. This is the language of the Midrash: With the strategy of a human king, Hashem brought the plagues upon them. A human king, when the country rebels against him, sends legions to surround it. Initially, he blocks their water supply. If they return, it is good; if not, he brings upon them k’lanim (various interpretations exist, possibly meaning chaos or minor afflictions). If they return, it is good; if not, he shoots arrows at them. If they return, it is good; if not, he brings legions upon them. If they return, it is good; if not, he brings dromasios (interpreted as severe afflictions). If they return, it is good; if not, he throws naphtha at them. If they return, it is good; if not, he throws ballista stones at them. If they return, it is good; if not, he incites many troops against them. If they return, it is good; if not, he imprisons them. If they return, it is good; if not, he kills their leaders.

Thus, the Holy One, blessed be He, came upon the Egyptians with the tactics of kings. Initially, He blocked their water supply, as it is said (Psalms 78:44), "He turned their rivers into blood, and their streams, they could not drink." But they did not return. He brought upon them k’lanim, which are the frogs, as it is said (Exodus 8:2), "Regarding the frogs, etc." But they did not return. He brought upon them arrows, which are the lice, as it is said (Exodus 8:13), "And the lice were on man and beast," as they would enter the bodies of the Egyptians like arrows. But they did not return. He brought upon them legions, which is the wild beasts, as it is said (Psalms 78:45), "He sent among them swarms of flies, which devoured them." But they did not return. He brought upon them dromasios, which is the pestilence. But they did not return. He threw naphtha at them, which is the boils. But they did not return. He threw ballista stones at them, which is the hail. But they did not return. Then He incited many troops against them, which is the locusts. Then He imprisoned them, which is the darkness, as it is said (Exodus 10:21), "And there was a thick darkness in all the land of Egypt." But they did not return. And He killed all their leaders, as it is said (Exodus 12:29), "And Hashem struck all the firstborn," thus concludes the Midrash.