Could the destroyer in Egypt discriminate?

Question

In Rashi's comment to Shemos 12:22 we read

ואתם לא תצאו וגו': מגיד שמאחר שנתנה רשות למשחית לחבל אינו מבחין בין צדיק לרשע
…once permission has been given to the משחית (destroyer) to damage, it does not distinguish between a righteous and a wicked person.

however earlier in pasuk 13 Rashi cites the mechilta which states

אבל הווה הוא במצרים הרי שהיה מצרי בביתו של ישראל, יכול ימלט, תלמוד לומר ולא יהיה בכם נגף, אבל הווה במצרי שבבתיכם, הרי שהיה ישראל בביתו של מצרי, שומע אני ילקה כמותו, תלמוד לומר ולא יהיה בכם נגף
…Thus, if an Egyptian were in an Israelite's home, you'd suppose he could escape [the plague]; the verse tells us "there won't be a נגף, plague, in you" — but there will be in the Egyptian in your homes. Thus, if an Israelite were in an Egyptian's home, I'd understand he'd be smitten like him; the verse tells us "there won't be a נגף, plague, in you".

1. Are the terms משחית and נגף equivalent? What "force" is doing the killing exactly?
2. Can whatever agency that is performing the killing on that night differentiate between Jew and Egyptian?
3. If it can discriminate, what is the need for the sign of the blood?
4. Why does Rashi in pasuk 22 contrast צדיק and רשע and not Jew/Egyptian?
5. Why is this destructive force able to differentiate between firstborn and non-firstborn of the Egyptians but nothing else?

Answer 1

The Maharal writes that although it was Hashem himself who killed the first-born, as we stress in the Haggada, permission was given to the destroyer. Usually the משחית doesn't have permission to wreak havoc on mankind. But during a מגפה the מלאך המות reigns freely.

This is alluded to in Bava Kamma, in Hakoness, that during a plague one should walk on the side of the road since the מלאך המות walks in the middle, whereas during good times one should walk in the main section to avoid the lurking מלאך המות.

So, Hashem is the one killing and He does differentiate between those whom He came to kill and the others. However, being that it was a time of plague there was free reign for evil powers to harm people indiscriminately.

According to this, נגף refers to Hashem's act while משחית is the angel of death.

Answer 2

1. The force is G-d himself, not a Malach. Source is obviously the Pesach Haggadah:

   Ani ve lo malach. Ani ve lo saraph. etc. (#57-59). Which Rashi himself (Exodus 12:12) comments to agree with this: will

I wreak judgments-I The Lord: I by Myself and not through a messenger. — [from Passover Haggadah]
אעשה שפטים אני ה': אני בעצמי ולא על ידי שליח:

2. G-d knows everything. Therefore He knows who is Jewish, who is Egyptian and exactly who is firstborn.

3. The ritual performed by the Israelites is not there to show who is one of them or not, but a commandment, primarily to show their commitment to being an Eved Hashem. They are switching one Avodah for a different one.

4. On verse 23 Rashi simply writes:

and He will not permit the destroyer: Heb. וְלֹא יִךְתֵּן, lit., and will not give. [I.e.,] He will not grant him the ability to enter, as in “but God did not permit him (נְתָנוֹ) to harm me” (Gen. 31:7)

ולא יתן המשחית: ולא יתן לו יכולת לבא, כמו (בראשית לא ז) ולא נתנו א-להים להרע עמדי:

5. Of course G-d can distinguish but this night in particular there is a certain miracle to take place, in which, at exactly midnight, all the Egyptian firstborns will be struck dead in one moment. Therefore nobody else will die that night, even those who normally would have done by the normal force of nature. This may be the meaning of not letting the destroyer to enter... Not even to take the lives of those who normally would have died that night.