“Yosef died, and all his brothers, and all that generation. And Bnei Yisroel were fertile and prolific; they multiplied and increased very greatly, so that the land was filled with them. A new king arose over Mitzrayim who did not know Yosef. And he said to his people, “Look, the people of Bnei Yisroel are much too numerous for us. Let us deal shrewdly with them, so that they may not increase; otherwise in the event of war they may join our enemies in fighting against us and rise from the ground.” So they set taskmasters over them to oppress them with forced labor; and they built fortified cities for Paroah: Pissom and Ramses. But the more they were oppressed, the more they increased and spread out, so that the (Mitzriyim) came to dread Bnei Yisroel” (Shemos1/6-12)
Concerning these pessukim the Medrash comments; These pessukim come to teach that as long as even one of the people who came down to Mitzrayim was still alive, the Mitzriyim did not enslave B'nei Yisroel and B'nei Yisroel were fruitful and multiplied. “Even though Yosef died Hashem didn't die." In other words, the Medrash teaches us that as long as there was some remnant of the generation who had left Eretz Yisroel to come down to Mitzrayim there was no enslavement or bondage. It was only after the last person of that generation died did the bondage begin.
The Unique Merit of the First Generation
Zera Shimshon asks what was that generation's unique quality that protected Bnei Yisroel from enslavement?
Secondly, what is the meaning of the phrase in the Medrash; "And even though Yosef died Hashem didn't die."? How could one even entertain such an impossible thought that Hashem died? It is so wrong that it contradicts two of the "Ani Maamin's"; the second one; "...that Hashem was, is, and will always be" and the fourth one; "...and Hashem is the first and will be the last."!
A third question; the Medrash connects the fact that Hashem still lives with the fact that "B'nei Yisroel were fruitful and multiplied." What is the connection?
The Role of Bris Milah
Zera Shimshon explains the first question in light of another Medrash and the answer is the key to answer the other two questions.
On the possuk "And a new king rose to power..." the Medrash explains, "When Yosef died (B'nei Yisroel) did away with milah ... And since they stopped to circumcise, Hashem replaced the love that the Mitzriyim had for them with hate...".
We see from the Medrash that two things happened when Yosef died. Firstly, at that time the situation in Mitzrayim got very bad for Bnei Yisroel. And secondly Bnei Yisroel stopped doing milah on their children.
Zera Shimshon learns from here that the special merit that those who came to Mitzrayim had, was that they performed the mitzvah of bris milah and it was the merit of bris milah that prevented them from suffering the pain of enslavement.
Although on the surface this answer seems good, a deeper look reveals that it is really not suffice. Zera Shimshon asks, although the second generation of children born in Mitzrayim after Yosef died were not circumcised, the children who were born in Mitzrayim but before Yosef died were circumcised? Why didn't the fact that they were circumcised prevent the enslavement to begin?
Zera Shimshon answers that, true, the people who were born in Mitzrayim before Yosef died were circumcised however they didn't make bris milah on their children and this canceled out the merit that they themselves were circumcised, like we learn in Mesechta Sotah, "a sin extinguishes a mitzvah". In other words, it was only the merit of being circumcised and circumcising their children that had the power to push off the bondage. This excludes the people who were born in Mitzriyim before Yosef passed away who even though they themselves were circumcised they didn't circumcise their children.
Hashem's Protection and the Loss of Merit
Understanding the difference between the generation that entered Mitzrayim and the generation after Yosef's death is that the former were circumcised while the latter were not is the key to understand why one might think "that Hashem died". Firstly, this phrase can't be taken at face value, like we mentioned before, since this would contradict two of the "Ani Maamim's". Rather it means that one might have thought that Hashem stopped taking care of Bnei Yisroel just like a deceased person cannot take care of a living person.
The reason a person could arrive at this false thought is that it was not incidental that after Yosef died Bnei Yisroel stopped doing bris milah. Zera Shimshon explains that since Yosef died they couldn't rely on him any more to protect them from the Mitzriyim so they stopped doing milah "to blend in" with the Mitzriyim and like this they felt safe. The fact that they didn't put their trust in Hashem to protect them is a good reason that Hashem will in fact not protect them!
Bris Milah and Fruitfulness
Having children is also connected with bris milah. This we see from the fact that right after Hashem commanded Avraham to do bris milah, Hashem promised Avraham many children as it is written (Braishis 17/16), "... I (Hashem) will bless her (Sarah) so that she shall give rise to nations; rulers of peoples shall issue from her.” Therefore one might think that since we didn't keep "our part of the deal" and we stopped doing milah then Hashem would not help Bnei Yisroel to have children. However the truth is that even though Bnei Yisroel didn't put their trust in Hashem and didn't do milah, Hashem continued to protect them and Hashem also helped that, "Bnei Yisroel were fertile and prolific; they multiplied and increased very greatly"!
A Thought from the Maharal
I would like to add a thought that is not written in Zera Shimshon but explains him.
Zera Shimshon only explains that the merit of milah prevented enslavement and bondage. Zera Shimshon doesn't, however, explain why this is.
However, I think that we can explain the connection according to a very important concept put forth by the Maharal.
Rashi in Parshas Bo writes that before our redemption from Mitzrayim, Hashem commanded us to circumcise ourselves and to bring the Karbon Pesach. The Maharal explains the reason for specifically these two mitzvos is that we weren't just redeemed from Mitzrayim to be free people. Rather, we were redeemed from being slaves and servants to Paroah and Mitzrayim in order to become servants to Hashem.
Therefore, explains Maharal, in order to become servants to Hashem we needed to serve Hashem. (Talk and declarations are cheap). We were therefore commanded to bring a Karbon Pesach in order to do an act of servitude for Hashem and our declaration that we are Hashem’s servants doesn't remain only words.
We also needed to show that we are now servants of Hashem. This is the reason for milah which is really "a symbol of servitude" (just like all slaves wear a marker, like we learn in Mesechta Shabbos)
According to this concept, we can understand the depth of Zera Shimshon. As long as Klal Yisroel was careful to circumcise themselves they proclaimed that they are servants or slaves to Hashem and therefore they ware privileged to special protection from Hashem like all masters protect their servants
However after they stopped being servants to Hashem they lost the special protection of their "master" (Hashem) and they were "fair game" to be enslaved by other masters.
