“The Lord spoke to Moses: Come to Pharaoh, and say to him: So said the Lord: Let My people go, and they will worship Me. If you refuse to let them go, behold, I will smite all your borders with frogs” (Exodus 7:26–27). “The Lord spoke to Moses: Come to Pharaoh.… If you refuse to let them go, behold, I will smite…” – that is what is written: “But the advantage of a land is in every way” (Ecclesiastes 5:8), and the entire midrash as it is written in Vayikra Rabba and in “This is the statute of the law” (Numbers 19:2):1See Vayikra Rabba 22:2; Bemidbar Rabba 18:22.
Our Rabbis say: “But the advantage of a land is in every way” – even items that you view as extraneous in the world, like flies, fleas, and mosquitos, they were included in the creation of the world, regarding which it is stated: “God saw everything that He had made [and behold, it was very good]” (Genesis 1:31). Rabbi Aḥa son of Rabbi Ḥanina said: Even items that you view as extraneous in the world, like snakes and scorpions, they were included in the creation of the world.
The Holy One blessed be He said to the prophets: ‘What do you think, that if you do not go on My mission I will have no emissary? “But the advantage of a land is in every way” – I will accomplish My mission even by means of a snake, or even by means of a scorpion, or even by means of a frog.’ Know that it is so, as were it not for the hornet, how would the Holy One blessed be He exact retribution against the Emorites,2See Sota 36a. and were it not for the frogs, how would He exact retribution from the Egyptians? That is what is written: “Behold, I will smite [all your borders with frogs].”