The purpose of the plagues and why the Jewish people were naturally protected until Makas Bechoros
(Likkutei Sichos Vol. 3)
Parshas Bo discusses the remaining plagues that G-d smote the Egyptians. The final plague, the plague of the death of the firstborn sons, came with an interesting oddity that we do not find by any of the previous plagues. While by all the previous plagues, or at least most of them, the Jewish people were naturally and automatically protected from being smitten, by the last plague of the death of the firstborn’s the Jewish people were required to make signs to be saved from being killed. This is most wondrous, as if by the other less severe plagues the Jewish people had enough merits to save them, then certainly they should of had enough merits to save them from the more severe plague of the death of the firstborns. To answer this question the Rebbe delves into the purpose of the plague of the firstborn versus all the other plagues. Every plague had its purpose, and in general these purposes were not relevant to the Jewish people, however the last plague had a purpose which could be also relevant to the Jewish people and therefore they needed a special protection
Explorations of the Sicha:
1. Why did the Jewish people need to make signs to save them from the plague of the death of the firstborn, if they were automatically protected from all the other plagues?
2. What was the significance of the blood of the sacrificial lamb and the blood of circumcision to merit the Jewish people to be saved from the plague of the first born?
3. What was the purpose of the plagues? Were they given as a punishment to the Egyptians, or did they have some other function?
4. What was the purpose of the last plague, the plague of the firstborn?
1. The difference between the plague of the firstborn and the previous plagues:
There are a number of differences that we find between the last plague, the plague of the firstborn, and all the other previous plagues. By all the previous plagues, the Jewish people were naturally and automatically saved from any harm, as the plagues only attacked the Egyptians and did not spread to the Israelites. There is nothing mentioned that the Jewish people had to do to gain this protection. The protection was granted automatically, and was self-understood to be the case, as G-d did so for the sake of helping save the enslaved Jewish people from their Egyptian captors. However, by the last plague, the plague of the firstborn, the Jewish people were specifically instructed to smear blood on their doorposts in order so they would not be susceptible to the angel of death. They were instructed to circumcise themselves and to slaughter the Pesach lamb and then take from that blood and smear it on the doorposts. They were also instructed not to leave their homes in order to be saved from death. This matter is quite wonderous, as if the Jewish people were not required to perform any actions by the previous plagues in order to receive protection, then why should this be necessary by the final plague which was much more severe? Also, we need to understand the connection between the signs that they were requested to do and the protection that it gained them.
2. By the plague of the firstborn, the angel of death was given free reign:
One of the differences between the plague of the firstborn and all the previous plagues is that by all the previous plagues, the punishment was limited, such as the plague of blood which targeted water, the plague of frogs which took place through frogs, the plague of lice which took place through lice, and so on and so forth. The plague of the firstborn, however, took place without any limitation, as the angel of death was given permission to kill freely with whatever tools he felt necessary. This unlimited leashing of power by the final plague is what made it necessary for the Jewish people to do something to protect themselves. There is, however, a deeper reason behind all of this, as we will now explain.
3. The purpose of all the plagues excluding the plague of the firstborn:
The main purpose of the plagues was not to punish the Egyptians, but rather to break their evil spirit, and make them recognize that G-d is the true G-d of the world. This is explicitly mentioned in Scripture by a number of the plagues, in which it states that it is being done in order so the Egyptians know G-d’s power. The Egyptian nation denied the existence of G-d and His ability to control the world as He wills. The purpose of the plagues was to prove to Pharaoh and the Egyptian nation, of the existence of G-d and of His great power. This purpose was unnecessary for the Jewish people, as they already believed in G-d and His capabilities and needed no proofs to convince them. Accordingly, there was no need for the Jewish people to also be susceptible to the plagues, as by them, the purpose of the plagues was already achieved. Likewise, it is for this reason that the plagues were not so severe and did not properly punish the Egyptians, and left many survivors, as their purpose was never to punish them and hurt them but rather to show them G-d’s miracles and wonders, and bring them to believe in G-d. However, the last plague of the first born was for a different purpose, and this purpose could’ve targeted also the Jewish people, as we will now explain.
4. The purpose of the plague of the firstborn:
Unlike all the previous plagues, the purpose of the last plague, the plague of the firstborn, was to actually punish the Egyptians for their sinful behavior. It was no longer about teaching them a lesson of G-d’s powers and capabilities, but rather to actually punish them, and kill all their firstborn without survivors. Now, once we are dealing with the subject of punishment for sinful activity, the Jewish people were not all that righteous either. The attribute of judgment can make a claim stating that just as the Egyptians are sinners and guilty of idol worship, so too there are many Jews who are guilty of the same, and hence under which right should only the Egyptians be targeted. It would be very difficult for the angel of death to differentiate between the Egyptian and Jew when both are guilty of the same crime that he is prosecuting. It is for this reason that the Jewish people needed to make a sign to both give them a merit for which they will be protected, and create a sign that will help the angel of death differentiate between Jew and Egyptian. We will now explore in greater detail the meaning of the blood which was smeared on the doorposts, and its significance in protecting the Jewish people
5. The reason the Jewish people needed to make signs by the plague of the firstborn:
The significance of the blood of the sacrificial lamb and the blood of the circumcision which the Jewish people were instructed to smear on their doorposts, rest within the challenge of their fulfillment. In order for the Jewish people to merit being saved from the angel of death that spared no firstborn on the night of the 15th, they had to perform a mitzvah of complete Mesirus Nefesh, illogical performance, which would then arouse the illogical within G-d and have their sins be ignored. By them doing a mitzvah which puts their own life in danger simply for the sake of G-d, it arouses a desire above within G-d to ignore even the most severe of sins. The slaughtering of the Passover lamb involved literal Mesirus Nefesh, as the sheep was considered an Egyptian deity, and through slaughtering it in public they put their very lives in danger. The illogical and irrational behavior of the Jewish people in circumcising themselves and slaughtering the Passover lamb likewise aroused an irrational, above intellect, interaction from G-d that He not exact punishment for their sins. Thus, we find that the sages state that it was in the merit of the two bloods, the blood of the Passover lamb and the blood of the circumcision, that we left Egypt.
The Divine lessons:
1. In the above talk we learned that the plagues, up until the last one, were not for the sake of punishment but simply for the sake of the Egyptians recognizing G-d. This can likewise teach us a very valuable lesson. Everything that happens to us in life has a purpose. Sometimes, when negative things happen to us it is G-d’s way of saying hello, to get our attention so we recognize Him and give him quality time, which is to make use of our minds to contemplate His existence and make use of our hearts to arouse feelings of love for Him.
2. Sometimes in order to merit a big blessing from G-d, something that is beyond our current merits, we must do something for G-d that is way above our capabilities, in the form of Mesirus Nefesh. This Mesirus Nefesh in a mitzvah can then serve as the conduit for the big blessing.
 See Shemos 7:17, 8:18, 9:14
 See Yalkut Reuveini Shemos 14:27; Zohar Chadash Parshas Yisro
 Pirkei Derebbe Eliezer 29; Mechilta Shemos 12:6