Rashi cites from this the first and the last part: one in five went up, and the others died in the days of darkness. It is an accepted tradition: HaShem killed eighty percent of the His nation during the days of darkness. The eighty percent is a scary number, because we know that the last redemption will be like the first."Another opinion: Chamushim Alu - one in five (went up from Egypt). Some say: one in fifty. Some say: one in five hundred. Rabbi Nehorai says: By the Temple service! Not even one in five hundred went up, as it is written: '[in your blood, live!, in your blood, live!] רבבה כצמ"ח השד"ה נתתי"ך (Ezechiel 16:6,7).' And it says: 'The children of Israel were fruitful and swarmed (Shemot 1:7).' And it was such that a woman would give birth to six children in one time. And you say that one in five hundred went up? By the Temple service! Not even one in five hundred went up, but many from Israel died in Egypt. When did they die? In the three days of darkness."
ד"א וחמושים עלו אחד מחמשה וי"א אחד מחמשים וי"א אחד מחמש מאות ר' נהוראי אומר העבודה לא אחד מחמש מאות עלו שנא' [ואמר לך בדמיך חיי ואמר לך בדמיך חיי] רבבה כצמח השדה נתתיך (יחזקאל טז ז) וכתיב ובני ישראל פרו וישרצו וירבו ויעצמו (שמות א ז) שהיתה האשה יולדת ששה בכרס אחד ואתה אומר אחד מחמש מאות עלו העבודה לא אחד מחמש מאות עלו אלא שמתו הרבה מישראל במצרים ואימתי מתו בשלשת ימי אפלה
What about the other opinions stated in the Mechilta? Is it conceivable that 98% were killed? And what about the opinion that the Mechilta stresses most? Is it possible that more than 99.8% were killed? Here, the Mechilta very likely speaks in code, and that is why Rashi and other commentators of Torah ignore it. It did not happen. Rather, the Mechilta conveys what should not be understood by all, as it speaks about the last exile and redemption in the language of the first exile and redemption. The days of darkness stand for the Galut, in which the only light is the light of Torah in Jewish houses. What were our Sages saying about the Galut?
I understand it as follows. It may be that one in five will go up: the Galut may be as short as five human generations - so that it would end around the time this Mechilta was likely written. However, the Galut could also take fifty human generations - so that it would end close to the year 6000. If a deserving generation will arise out of the Galut, all of its millions will go up. However, if - after fifty generations - a non-deserving nation will be redeemed, it is possible that no more than ten percent of them will go up, or even fewer. Our Sages used the code of the Mechilta to emphasize the likelihood of the latter scenario.
Now, if 80000 myriads died without seeing the Geula, the one-in-fifty deserving generation would number 16 million Jews, 800 million divided by 50. We must conclude that we are not a deserving generation. This must be one lesson of the Holocaust, after which far less than 16 million Jews remain. There is another lesson. If one in fifty is 16 million, one in five hundred is 1.6 million. The Jewish population of Eretz Yisrael counts already many more than 1.6 million souls. Ezekiel 16:6 auspiciously repeats the phrase "in your blood, live!" About 7.6 million Jews still live outside of the Land of Israel. It can happen again.
