The eighth plague, Arbeh, locusts, is presented in the beginning of Parashat Bo, but its presentation differs from that of previous plagues. Hashem tells Moshe Rabbeinu, “Bo El Par’oh, Ki Ani Hichbadti Et Libo VeEt Leiv Avadav Lema’an Shiti Ototai Eileh BeKirbo,” “Come to Par’oh, for I have hardened his heart and the heart of his servants, in order that I may place these signs of Mine in his midst” (Shemot 10:1). Interestingly, Hashem commands Moshe to go to Par’oh, but the Torah does not say anything about what Moshe is supposed to tell Par’oh. The Torah does not reveal the nature of the eighth plague until a few Pesukim later, when Moshe and Aharon go to Par’oh and warn him that “Im Ma’ein Atah LeShalei’ach Et Ami, Hineni Meivi Machar Arbeh BeGevulecha,” “If [Par’oh] refuses to let [B’nei Yisrael] go, behold, tomorrow [Moshe] will bring locusts into [Par’oh’s] borders” (Shemot 10:4). If the Jews are not let out to worship Hashem, Hashem will send locusts. The Torah’s record of the Plague of Arbeh appears strange: why does it omit Hashem telling Moshe Rabbeinu what Moshe is supposed to tell Par’oh but record Moshe telling Par’oh?
The Ramban believes that there is no question; the Torah is just more succinct by Arbeh than by other plagues. The Ramban compares this brevity to the plague of hail, when the Torah records Hashem’s words to Moshe but does not record Moshe’s warning to Par’oh. Furthermore, claims Ramban, Hashem’s words to Moshe do hint to locusts. In the second Pasuk of the Parasha, Hashem explains the reason for the upcoming plague, “Lema’an Tesapeir BeOznei Vincha UVen Bincha Eit Asher Hit’alalti BeMitzrayim,” “in order that you tell into the ears of your son and your son's son how I made a mockery of the Egyptians” (Shemot 10:2). The Ramban believes that the Pasuk hints to locusts because of a parallel Pasuk in the book of Yoel. Hashem tells Yoel, “Aleha LiVneichem Sapeiru, UVneichem LiVneihem, UVneihem LeDor Acheir, Yeter HaGazam Achal HaArbeh,” “Tell your children about it, and your children to their children, and their children to another generation, ‘what the cutter left over, the locust devoured’” (Yoel 1:3-4). Both Shemot 10:2 and Yoel 1:3 talk about that the Jews telling their children and grandchildren about an event, and in both places, the event concerns Arbeh, locusts. Ramban associates “telling children and grandchildren” with locusts, so when Hashem told Moshe and Aharon to tell their children about the plague, He was hinting to locusts.
Many authorities do not accept Ramban’s dismissal of the question. Why is the plague of locusts written in the Torah in a different way than all the other plagues, going more in depth than usual into Moshe and Par’oh’s encounter? Rav Hirsch gives an answer: he reasons that the Torah focuses on Moshe and Par’oh’s meeting because there is something special about that interaction. This special quality is what Moshe and Aharon say to Par’oh “Ad Matai Mei’anta Lei’anot MiPanai,” How long will you refuse to humble yourself before Me?” (Shemot 10:3). The locust is special because it teaches Par’oh to be humble.
How does the plague of locusts teach humility to Par’oh? Before we can answer this, we have to understand the difference between the plagues of hail and locusts and between all the other plagues. The Kli Yakar (9:30) explains that the Pesukim between the plagues of hail and locusts not only say that Hashem hardened Par’oh’s heart--they also say, uniquely from the other plagues, that Hashem hardened the hearts of the common Egyptians. The Kli Yakar states that the reason the Pasuk mentions both is because the commoners were affected by both of those plagues more than Par’oh. Par’oh had storehouses for extra crops but the commoners did not, so when the hail and locusts came, they had no food, while Par’oh still had some.
Using the idea that the plagues of hail and the locusts affected the commoners more than Par’oh, we can now answer the question of how the plague of locusts teaches Par’oh humility. The Midrash (Shemot Rabba 8:2) informs us that Par’oh made himself like a god. The plague of locusts taught Par’oh humility because the whole country came to him asking for help, but he could not help them because he had little food. These plagues humbled him because he was rendered helpless, a very un-godly feeling.
Why did the plague of hail not do the job of the locusts (teaching Par’oh humility)? The answer is that the hail did not destroy all the crops (Shemot 9:32), so when the people came to Par’oh for food, he could tell them to eat their remaining crops. However, when the locusts came, they finished off the crops, so Par’oh could not help his people.