1. The Plague of the Firstborn was intended to secure Bnai Yisrael’s freedom
The above passage introduces the last of the ten plagues – the Plague of the Firstborn. Hashem describes the plague to Moshe. Moshe then warns Paroh that this terrible plague will be brought upon him and Egypt if he does not allow Bnai Yisrael to leave the Land. Paroh refuses to heed Moshe’s warning and the plague strikes Egypt. The impact of the plague is unbearable and Paroh is forced to release Bnai Yisrael.
In the above passage, Hashem tells Moshe that this plague will force Paroh to release Bnai Yisrael. This suggests that although Hashem was prepared to force Paroh and the Egyptians to liberate Bnai Yisrael, for some reason, He delayed this horrible plague until this point. In other words, Hashem’s intent in bringing the plagues upon Egypt was not solely to secure the freedom of Bnai Yisrael. If this were His sole purpose, this outcome could have been secured much earlier.
For now, I could have sent out My hand and struck you and your nation with pestilence and you would have been removed from the land. But in truth, for this reason I have sustained you – in order to demonstrate to you My strength and in order that My name will be declared in all the land. (Sefer Shemot 9:15-16)
2. The first nine plagues were not designed to secure Bnai Yisrael’s freedom
The above passages are part of the warning that Moshe delivered to Paroh after the Plague of Pestilence and before the Plague of Boils. The Plague of Pestilence decimated the Egyptians’ livestock. However, this pestilence did not affect humans – only animals. Moshe tells Paroh that had Hashem wished, He could have extended the plague’s affect. He could have directed the pestilence against the Egyptian people and not only against their livestock. However, He fashioned the plague in a manner that limited its damage and allowed the Egyptian people to survive. Hashem spared the Egyptians from eradication.
This passage provides additional confirmation of the message implicit in the first passage above. Hashem did not bring the plagues upon the Egyptians solely to coerce Paroh to release Bnai Yisrael. Some other objective was served through the plagues.
This means that the Plague of the Firstborn was fundamentally different from the other plagues. The Plague of the Firstborn was intended to secure the release of Bnai Yisrael. This plague was preceded by nine other plagues. These plagues were not designed to secure Bnai Yisrael’s release. These plagues had some other objective.
And you should say to Paroh, “So says Hashem: Israel is My firstborn son. I say to you send out My son that he may serve Me. If you refuse to send him out, I will kill your firstborn son.” (Sefer Shemot 4:22-23)
3. Hashem revealed to Moshe the Plague of the Firstborn when He assigned him his mission
Rav Yitzchak Zev Soloveitchik Zt”l notes this distinction between the Plague of the Firstborn and the preceding plagues. He adds that this distinction explains an odd set of passages found earlier in Sefer Shemot. Hashem commands Moshe to return to Egypt and assigns him the mission of redeeming Bnai Yisrael. He tells Moshe to confront Paroh; demand the release of Bnai Yisrael, and warn him that if he resists, he will be subjected to the Plague of the Firstborn. It is odd that Hashem tells Moshe of the final plague before revealing to him the preceding nine plagues. Furthermore, Hashem describes the warning Moshe will deliver before the final plague is brought upon Egypt. However, Moshe is not instructed to deliver this warning until all of the preceding plagues have been brought upon the Egyptians. Why does Hashem describe to Moshe the plague and its warning at this point? It would have made more sense for Hashem to wait until the time had arrived for the final plague. At that moment, He should have revealed the plague to Moshe and instructed him to warn Paroh.
Rav Soloveitchik responds that in the context of the discussion described in the passages these instructions are relevant and appropriate. Hashem is sending Moshe to Egypt with the mission of leading Bnai Yisrael forth from bondage. He assigns Moshe this mission and reveals to him the instrument through which the mission will be fulfilled. This instrument is the Plague of the Firstborn. It is this plague that will coerce Paroh to release the people. This is not the function of the other plagues. Therefore, in charging Moshe with his mission, he communicates to him the instructions regarding the final plague and does not mention those that will precede it.
What was the function of these preceding plagues?
And Hashem said to Moshe: Behold, I have appointed you as a judge over Paroh and Aharon your brother will be your spokesperson. (Sefer Shemot 7:1)
4. Moshe was Paroh’s judge
Hashem speaks to Moshe. He tells Moshe that he has been appointed as Paroh’s judge. Rashi comments that with this statement Hashem transmitted to Moshe the authority to judge and punish Paroh. This means that the process that unfolded with Moshe’s arrival in Egypt was not only one of redemption for Bnai Yisrael. Moshe was charged with a second mission. He was appointed as judge and executioner of the Paroh and the Egyptians. Rav Soloveitchik explains that this appointment reveals the role of the first nine plagues. These plagues were not intended to secure the release of Bnai Yisrael. These plagues were intended to punish the Paroh and his people for their persecution of Bnai Yisrael.
And He said to Avram: You should know that your descendants will be aliens in a land that is not theirs. They (the inhabitants) will subjugate them and afflict them for four hundred years. But this nation that they will serve I will judge and afterward they will go forth with great wealth. (Sefer Beresheit 15:13-14)
5. The dual objective of the plagues was revealed to Avraham
These passages were part of a prophecy and a covenant entered into by Hashem and Avraham. Hashem foretold Avraham of the bondage of his descendants in Egypt. Also, He revealed to Avraham that his descendants’ bondage will end with the judgment of their oppressors and their own redemption. Rav Soloveitchik explains that this covenant was the basis for the design of the plagues. The plagues fulfilled this ancient promise. They punished Bnai Yisrael’s oppressors and they secured their release from bondage.
One of the greatest mysteries of the Torah’s account of Bnai Yisrael’s redemption is its description of Hashem suspending Paroh’s freewill. The Torah explains that Hashem instructed Moshe to warn Paroh of the consequences of continuing to enslave Bnai Yisrael. Before many of the plagues, Moshe goes to Paroh and warns him. He tells Paroh that if he does not release the people, he will experience another plague. However, the Torah also reveals that Hashem hardened or strengthened Paroh’s heart. He deprived Paroh of the volition to heed Moshe’s warning. A bizarre routine evolved. Moshe warned Paroh; Paroh was prevented from acquiescing; the plague was brought upon Paroh and Egypt.
In itself, this suspension of volition implies that the first nine plagues were not designed to secure Bnai Yisrael’s freedom. If that was their design, it would not make sense for Hashem to deprive Paroh of the capacity to surrender Bnai Yisrael. Rav Soloveitchik’s conclusions provide a simple solution for this mystery.
It is possible that a person will commit a great sin or many sins and the judgment of the True Judge will be that the punishment for this willfully committed sin or sins will be that he is prevented from repenting. He (the sinner) is not provided the volition to repent from his wickedness. This is in order that he should die and be destroyed for the sin he has committed… Therefore, it is written in the Torah, “I will strengthen the heart of Paroh”. Because he first sinned by his own volition and acted evilly to the people of Israel who dwelled in his land … it was the judgment that repentance should be denied him so that he should be punished. Therefore, Hashem strengthened his heart… (Maimonides, Mishne Torah, Laws of Repentance 6:3)
6. The suspension of Paroh’s freewill
Maimonides’ comments respond to a difficult issue. One of the fundamental principles of the Torah is that human beings are endowed with freewill – the capacity to make their own moral decisions. Because we have freewill, Hashem revealed to us His commandments, rewards us for our observance of them, and holds us responsible for their violation. Maimonides asks: How can we reconcile the principle of free choice with various passages in the Torah that indicate instances in which specific individuals or people have been deprived of their freewill? Maimonides cites as an example the Torah’s description of Hashem strengthening Paroh’s heart and depriving him of the ability to respond to the plagues by releasing Bnai Yisrael. In other words, the Torah tells us that Paroh would have surrendered Bnai Yisrael in response to the plagues if he had freewill. However, he was deprived of the ability to choose freely. Therefore, despite the suffering that he and his nation experienced, he could not release Bnai Yisrael.
Maimonides responds that in this instance Paroh was only deprived of volition after he had acted with terrible wickedness. He made freewill choices to oppress, afflict, and murder Bnai Yisrael. As a consequence of these freewill choices, he was punished by losing the ability to repent. His freewill was suspended in order to assure that he would be punished for his wickedness.
With these comments, Maimonides reconciles the principle of freewill with the passages in the Torah that suggest that freewill can be suspended. He also provides an important insight into the mystery of Hashem’s treatment of Paroh. Hashem deprived Paroh of freewill as punishment for his willful wickedness. He then brought the plagues upon him. Moshe’s warnings demonstrated Paroh’s helplessness. Even after being warned by Moshe, he could not repent. His volition was suspended.
In the course of answering his own question, Maimonides confirms Rav Soloveitchik’s position that the plagues were intended as a punishment for Paroh and the Egyptians. Hashem gave Paroh the ability to withstand the plagues so that he would be punished with additional plagues. Clearly, Maimonides understands the plagues as an instrument of punishment and not merely as a coercive measure designed to force Paroh to release Bnai Yisrael.
To the One Who struck the Egyptians through their first born – for His kindness is eternal. (Tehilim 136:10)
7. Understanding Hallel HaGadol
It is customary to recite the 136th chapter of Psalms on Shabbat and festivals. This chapter is referred to as Hallel HaGadol – the Great Praise. The chapter begins with a number of more general praises. The tenth passage begins a series of praises that focus on the acts of kindnesses Hashem performed for Bnai Yisrael – beginning in Egypt. The first of these kindnesses is identified as the Plague of the Firstborn. The chapter does not mention the nine preceding plagues. This implies that these plagues were not performed as a kindness towards Bnai Yisrael. This characterization and the contrast between the first nine plagues and the final plague conforms to Rav Soloveitchik’s conclusions. The first nine plagues were intended as punishment for the Egyptians. They were not designed as a kindness towards Bnai Yisrael. In contrast, the final plague – the Plague of the Firstborn – was intended to force Paroh and the Egyptians to release Bnai Yisrael. This plague was a kindness performed on behalf of Bnai Yisrael.
 Rabbaynu Shlomo ben Yitzchak (Rashi), Commentary on Sefer Shemot 7:1.
 Rav Yitzchak Zev Soloveitchik, Chidushai MaRan RIZ HaLeyve on the Torah, Parshat VaEyrah, Rav Y. Hershkowitz, Netivot Raboteynu, vol 1, pp 290-292.