The classic position adopted by most Midrashim and numerous commentators is that all Ten Plagues distinguished by ethnicity, afflicting only the Egyptians while sparing the Israelites. This approach is the logical extension of the perspective that the purpose of the Plagues was to punish the Egyptians while preventing the suffering of the Israelites. It thus expands the scope to from five to ten and maximizes the miraculous nature of the process. In order to do so, it must posit that there were many supernatural phenomena which are not explicitly recorded in the text.
Other commentators prefer to view the process of the Plagues as less of a deviation from the laws of natural order, and they achieve this in two different ways. The Moshav Zekeinim and Shadal maintain that there was differentiation in all of the Plagues, but propose that it was geographic in nature, distinguishing between the lands of Goshen and Egypt proper, rather than between two nations. In contrast, more rationalist commentators such as Ibn Ezra, Ralbag, and Ibn Kaspi limit the scope of the separation to only the five more severe plagues in which it is mentioned explicitly in the Torah.
The most unique approach is that of the Akeidat Yitzchak, who develops the idea that the main objective of the differentiation (and the Plagues themselves) was to serve as an educational tool to teach Paroh a series of lessons about the powers of Hashem. The Plagues thus formed a progression which started with no differentiation in the early ones, continued with geographic separation, and then reached a climax with the more miraculous ethnic distinction.
Commentators differ both as to whether Hashem distinguished between the Egyptians and Israelites in all of the Plagues or only in some of them, and also regarding the nature and purpose of His distinction:
Differentiation in All Ten Plagues
All Ten Plagues targeted only the Egyptian people or country, while the Israelites emerged virtually unscathed.
Ethnic
The Plagues struck the entire Egyptian population regardless of their location, but spared the Israelites even if they were outside of Goshen.
Israelites fully protected – This approach rejects the possibility that there was collateral damage to the Israelites in any of the Plagues. See the remarks of the TurLong Commentary Shemot 7:25About R. Yaakov b. Asher who emphasizes that Hashem is certainly not lacking the means to deliver His punishments only to the wicked. See also the Radbaz who points out that had also the Israelites been afflicted, the message of the Plagues would have been lost on Paroh.3
Natural or supernatural – This position views the Ten Plagues as a completely miraculous process which contravened the laws of natural order and was able to distinguish between an Egyptian and an Israelite standing next to each other.4 As this distinction was an overt miracle, there is no reason to assume that it applied only in some of the Plagues.5
"Ten miracles were performed for Israel in Egypt" – The Rambam6 interprets this Mishna in Masekhet AvotAvot 5:4About the Mishna as referring to the miraculous differentiation in each and every one of the Ten Plagues.7
Purpose of the Plagues and their differentiation – Philo and the Midrashim emphasize different aspects:
Philo suggests that the extraordinary differentiation was designed to teach the Israelites piety, as it demonstrated in the clearest way possible the punishment of the wicked and the salvation of the righteous. This fits well with Philo's general view of the Plagues as an educational tool. See Purpose of the Plagues.
In contrast, Tanchuma and Shemot Rabbah view the Plagues as a retributive (מידה כנגד מידה) process. From this perspective, it is logical that all of the Plagues were directed solely at those who deserved punishment.
Differentiation mentioned only in five plagues – According to this approach, it is difficult to understand why the Torah notes this overtly miraculous phenomenon only in some of the Plagues.8 The Rambam9 thus attempts to find textual hints for a distinction being made in each of the Plagues.10 However, even if his interpretations are accepted, there remains a significant disparity between the Plagues regarding the degree of emphasis placed on the differentiation.
Differentiation noted in the warnings of only three plagues – This approach does not account for why in the Plagues of עָרֹב, דֶּבֶר, and בְּכוֹרוֹת Paroh needed to be told about the differentiation in advance.11
The Israelites' Egyptian neighbors – Philo, Tanchuma, and Shemot Rabbah portray the Egyptians and Israelites as living together and sharing even the same homes. For more, see Where Did the Jews Live.
No עָרֹב in Goshen ("וְהִפְלֵיתִי... אֶת אֶרֶץ גֹּשֶׁן") – These sources would explain that the safety net afforded by the land of Goshen worked only for the Israelites, as indicated by the subsequent verse "וְשַׂמְתִּי פְדֻת בֵּין עַמִּי וּבֵין עַמֶּךָ".12
No בָּרָד in Goshen ("רַק בְּאֶרֶץ גֹּשֶׁן אֲשֶׁר שָׁם בְּנֵי יִשְׂרָאֵל") – These sources would explain that "אֲשֶׁר שָׁם בְּנֵי יִשְׂרָאֵל" limits the protection of Goshen to the Israelites only.
Light for the Israelites "בְּמוֹשְׁבֹתָם" – Shemot Rabbah learns from here that the Israelites had light any place they were, and not just in Goshen.
Geographic
The Plagues were visited only upon the land of Egypt, but did not touch the land of Goshen.
Israelites outside of Goshen and Egyptians in Goshen – Shadal "admits" that according to this position it is necessary to say that Israelites who were outside of Goshen were afflicted by at least some of the Plagues.14 Conversely, the logical upshot of this position is that the Egyptians in Goshen were spared.15
Natural or supernatural – Since who the Plagues struck or did not strike was based on geographical location, rather than on an individual's religious identity, the phenomenon did not need to violate the laws of natural order. Furthermore, if the Plagues were a chain reaction, differentiation between Goshen and Egypt proper in the initial plagues would have naturally resulted in continued distinction throughout the series.16
Differentiation mentioned only in five plagues – The Moshav Zekeinim explains that since the first three plagues came from the water and the earth, it was obvious that they were localized.17 Only in airborne plagues which came from afar was there a need to specify that they did not spread to Goshen.18
Differentiation noted in the warnings of only three plagues – The Moshav Zekeinim notes that the Plagues of עָרֹב, דֶּבֶר, and בְּכוֹרוֹת are unique in that they are the only ones which came directly from Hashem without any action of Moshe or Aharon. Therefore, their warnings needed to give Paroh an additional sign to demonstrate that their arrival was not just mere coincidence.19
Paroh checks only after דֶּבֶר – The Moshav Zekeinim explains that by עָרֹב, Moshe's ability to also remove the Plague amply demonstrated that it was a Divine punishment, and there was no need for Paroh to check whether the Plague had differentiated. It was only after דֶּבֶר where there was no active removal of the Plague, that Paroh needed to do a spot check.
The Israelites' Egyptian neighbors – Shadal maintains that the vast majority of Israelites lived in Goshen, and perhaps only a scant minority did not.20 Thus, he is able to minimize the harmful consequences for the Israelite population. According to this, the Israelites' Egyptian neighbors described in the Torah must be in Goshen itself.21
No עָרֹב, בָּרָד or חֹשֶׁךְ in Goshen – The verses "וְהִפְלֵיתִי... אֶת אֶרֶץ גֹּשֶׁן" and "רַק בְּאֶרֶץ גֹּשֶׁן אֲשֶׁר שָׁם בְּנֵי יִשְׂרָאֵל" work well with this approach. Shadal adds that the verse of "וְשַׂמְתִּי פְדֻת בֵּין עַמִּי וּבֵין עַמֶּךָ" is part of a פרט וכלל which also refers to this same location based separation.22 Similarly he interprets "בְּמוֹשְׁבֹתָם" in the Plague of Darkness as meaning "בארץ מושבותם", or the land on which the Israelites lived.23
Israelites spared in מכת בְּכוֹרוֹת – Shadal says that the Plague of the Firstborn was unique from all of the previous ones in that it distinguished on the basis of ethnic identity. He adds that, because of the miraculous nature of this differentiation, the Torah attributes the passing from house to house to Hashem Himself.
Combination of Factors
The Plagues differentiated using a combination of ethnic and geographic factors, with differences existing between the various plagues. The commentators present a few variations of this possibility.
Israelites outside of Goshen – All of these sources appear to maintain that in most of the Plagues, Israelites outside of Goshen were not spared. However, they all note at least one exception, while differing as to that plague's identity. Rashbam says that the Plague of Darkness was an exception, the Tosafist manuscript contends that דֶּבֶר was an exception, while Ramban suggests that עָרֹב was an exception.26
Egyptians in Goshen – From Ramban it would seem that Goshen afforded protection even for the Egyptians living there throughout all of the Plagues. According to the Tosafist manuscript, though, this was a unique feature of the Plague of עָרֹב.27
Differentiation mentioned only in five plagues
Rashbam and Ramban explain that there is a need to specify that Hashem distinguished only in plagues that tend to spread.28
The Tosafist manuscript says that the Torah notes the differentiation only when it incorporates a special aspect that didn't exist in the rest of the Plagues. Thus, it suggests that while all of the Plagues spared the Israelites who lived in Goshen, עָרֹב was unique in that it did not harm even the Egyptians in Goshen, and דֶּבֶר was unique in that it did not affect the Israelites outside of Goshen.29
Paroh checks only after דֶּבֶר – The Tosafist position that דֶּבֶר was the only plague which spared even Israelites outside of Goshen would account for why it is also the only plague after which Paroh checks to see who was affected.30
Differentiation Starting From Second Triad
The last seven plagues with the exception of the Plague of Locust afflicted only the Egyptians, while the first three plagues hit even the Israelites.
Structure of the Plagues – The Akeidat Yitzchak splits the Ten Plagues into three categories, each of which was intended to teach a different fundamental principle.31
Purposes of the Plagues and their differentiation – R. Yitzchak Arama proposes that the sets of plagues form a progression. The first three plagues were intended merely to demonstrate Hashem's existence, and thus they did not differentiate.32 The second set of three plagues was designed to showcase Hashem's ability to distinguish between nations, and therefore they needed to differentiate. The third set of three plagues were brought to show Hashem's unlimited powers to override the laws of nature, and thus they also differentiated.33 Thus, according to the Akeidat Yitzchak, the purpose of the differentiation was not merely to spare the Israelites from harm, but to demonstrate to Paroh the greatness of God.34
Why mentioned in only five? – R"Y Arama explains that differentiation is not mentioned in the first three plagues as they did not come for this purpose and thus did not distinguish. Starting from the second triad, differentiation is mentioned, as Divine providence was the cardinal lesson imparted by these plagues. To sustain this interpretation, though, he must account for the absence of explicit differentiation in the Plagues of שְׁחִין and אַרְבֶּה. This he does with two different claims:
שְׁחִין – The Akeidat Yitzchak maintains that this plague also affected only the Egyptians. He attempts to prove this by arguing that the Egyptian magicians would not have been embarrassed to stand in front of Moshe, if Moshe and Aharon and all of the Israelites were also afflicted by the Plague.35
אַרְבֶּה – The Akeidat Yitzchak holds that this plague is the only one of the last seven which affected even the Israelites. He explains that this was part of a scorched earth policy designed to prevent the Egyptians from being left with crops to harvest after the Israelites' departure.36
Differentiation noted in the warnings only of עָרֹב, דֶּבֶר, and בְּכוֹרוֹת – This approach would explain that the emphasis in the preludes to עָרֹב and דֶּבֶר is because Hashem's power to differentiate is the raison d'être of the second triad of plagues.37 One could go a step further and suggest that it was only in the middle set of plagues and final plague that the purpose of the differentiation was to teach Paroh a lesson, but that in the other plagues the goal was merely to protect the Israelites.
Paroh checks specifically after דֶּבֶר – According to the Akeidat Yitzchak, the Plague of דֶּבֶר was a turning point, as it was the first plague to demonstrate Hashem's ability to differentiate ethnically among people living in the same location.
Ethnic or geographic – the variation between עָרֹב and דֶּבֶר – According to the Akeidat Yitzchak, the differentiation during the Plague of עָרֹב was geographic and protected everyone in Goshen. However, when Paroh was unimpressed by this, the differentiation in דֶּבֶר became ethnically based and even more miraculous.
No dual discrimination in עָרֹב – This approach would need to understand that "וְהִפְלֵיתִי... אֶת אֶרֶץ גֹּשֶׁן" and "וְשַׂמְתִּי פְדֻת בֵּין עַמִּי וּבֵין עַמֶּךָ" both refer to a location based differentiation.38
Israelites outside of Goshen and Egyptians in Goshen in דֶּבֶר – It is unclear whether R"Y Arama maintains that the method of differentiating in דֶּבֶר expanded, supplanted, or narrowed the safety net afforded by the previous עָרֹב method. In other words, there are three ways to understand the impact of the new method of ethnic profiling:
It was designed only for Egypt proper, and Goshen continued to provide a safe haven even for Egyptians.39
It simply replaced the previous geographical distinction, and now all Israelites but no Egyptians would be saved.40
It was intended to narrow the scope of the previous protection of Goshen to Israelites only.41
No בָּרָד in Goshen ("רַק בְּאֶרֶץ גֹּשֶׁן אֲשֶׁר שָׁם בְּנֵי יִשְׂרָאֵל") – It is unclear why this verse reverts to emphasizing the geographically based distinction. It is possible that the Akeidat Yitzchak would contend that the ethnically based differentiation was reserved only for the Plagues of דֶּבֶר and בְּכוֹרוֹת (as this was the central message of these plagues), but that the intervening plagues distinguished only by location.42 Alternatively, this verse can be interpreted as saying that only the Israelites in Goshen were spared.43
Differentiation Only in Five Plagues
While five of the Plagues targeted only the Egyptians, the other five affected even the Israelites.44
Ethnic
The five plagues which did distinguish afflicted the entire Egyptian population regardless of their location, but did not harm any of the Israelites even those outside of Goshen.
Sources:
Israelites fully protected but only in these five plagues – This approach could explain like Ibn Ezra below that there was differentiation only in the most severe plagues.45 The purpose of the differentiation would be for the sake of the Israelites' survival.
Differentiation noted in the warnings of only עָרֹב, דֶּבֶר, and בְּכוֹרוֹת – This position could maintain that the distinction between Goshen and Egypt is not mentioned in the prelude to בָּרָד because even in Egypt one could avoid harm by staying inside one's home. By the Plague of Darkness, there is no warning whatsoever.
No עָרֹב in Goshen ("וְהִפְלֵיתִי... אֶת אֶרֶץ גֹּשֶׁן") – The safety net afforded by the land of Goshen worked only for the Israelites, as indicated by the subsequent verse "וְשַׂמְתִּי פְדֻת בֵּין עַמִּי וּבֵין עַמֶּךָ".46
No בָּרָד in Goshen ("רַק בְּאֶרֶץ גֹּשֶׁן אֲשֶׁר שָׁם בְּנֵי יִשְׂרָאֵל") – The words "אֲשֶׁר שָׁם בְּנֵי יִשְׂרָאֵל" limits the protection of Goshen to the Israelites only.
Light for the Israelites "בְּמוֹשְׁבֹתָם" – The Israelites had light any place they were, and not just in Goshen.
Israelites spared in דֶּבֶר and מכת בְּכוֹרוֹת – The verses by these plagues work well with this position.
Geographic
The five plagues which did distinguish came only upon the land of Egypt, but did not touch the land of Goshen.
Israelites outside of Goshen and Egyptians in Goshen – Ibn Kaspi says that the Israelites who were enslaved in Egypt proper were affected by all of the Plagues.48
Natural or supernatural – This more rationalist approach limits the miraculous aspects of the Plagues to what is explicit in the text.49
Purpose of the differentiation and why only in these five plagues? Ibn Kaspi appears to understand that the differentiation was to protect the Israelites, and it existed only in the Plagues whose harmful effects were severe or fatal.50
Differentiation noted in the warnings only of עָרֹב, דֶּבֶר, and בְּכוֹרוֹת – Ibn Kaspi does not explicitly address this issue, but he could explain like the Moshav Zekeinim above.
The Israelites' Egyptian neighbors – According to Ibn Kaspi, the Israelites all lived in Goshen, although many were enslaved in the Egyptian cities. The Egyptian neighbors which they had were in Goshen.51
No עָרֹב, בָּרָד or חֹשֶׁךְ in Goshen – The verses "וְהִפְלֵיתִי... אֶת אֶרֶץ גֹּשֶׁן" and "רַק בְּאֶרֶץ גֹּשֶׁן אֲשֶׁר שָׁם בְּנֵי יִשְׂרָאֵל" work well with this approach, and Ibn Kaspi interprets "בְּמוֹשְׁבֹתָם" in the Plague of Darkness as also referring to the land of Goshen.
Israelites spared in דֶּבֶר and מכת בְּכוֹרוֹת – Ibn Kaspi would likely explain that all of the Israelites' cattle was in Goshen, and that the Israelites all returned to their homes in Goshen at night, or at least on the night of Pesach.
Combination of Factors
The five plagues which did differentiate, did so using a combination of ethnic and geographic factors. There are a couple of variations of this option.
Israelites outside of Goshen and Egyptians in Goshen
Ibn Ezra's position with regard to the plagues other than עָרֹב is not completely clear.52 In עָרֹב he maintains that both the Israelites outside of Goshen and the Egyptians in Goshen were saved.
Ralbag says that עָרֹב spared only the Israelites in Goshen, but afflicted both the Israelites outside of Goshen and the Egyptians in Goshen. Similarly, by the Plague of Darkness he states the Egyptians in Goshen were affected.
Purpose of the differentiation and why only in these five plagues? The differentiation was for the sake of the Israelites, and thus Ibn Ezra explains that there was no need for differentiation in the less harmful plagues.53 He adds that there was no need to protect the Israelite crops in the Plague of Locust since the Exodus was imminent.54
Differentiation noted in the warnings only of עָרֹב, דֶּבֶר, and בְּכוֹרוֹת – This approach does not address this issue but could explain like the Moshav Zekeinim above.
The Israelites' Egyptian neighbors – According to Ralbag, the Israelites all lived in Goshen, as did the group of Egyptians who were their neighbors. For more, see Where Did the Jews Live.
Dual discrimination in עָרֹב – These commentators disagree as to how to understand the relationship between "וְהִפְלֵיתִי... אֶת אֶרֶץ גֹּשֶׁן" and "וְשַׂמְתִּי פְדֻת בֵּין עַמִּי וּבֵין עַמֶּךָ":
Ibn Ezra interprets that the two verses complement each other, and there were two processes of differentiation. The result was that the Plague spared both everyone in Goshen (including Egyptians) as well as all Israelites everywhere.55
Ralbag takes the opposite view, explaining that the two verses limit each other and there was only a single process of differentiation which spared only the Israelites living in Goshen.