Commento su Esodo 9:9

לשחין פרח אבעבעת A BOIL BREAKING FORTH INTO BLAINS — Render it as the Targum does: a boil growing blains, — the idea is, that through it (the boil) blains burst out on them (on the people).

AND IT SHALL BECOME SMALL DUST OVER ALL THE LAND OF EGYPT. According to the opinion of our Rabbis,²⁰⁴Shemoth Rabbah 11:6. [the small quantity of] soot [in the hands of Moses] became the dust which settled over the whole land of Egypt, and that dust, coming upon man and upon beast, caused them to break forth with boils and blains throughout all the land of Egypt, since it was a burning hot dust. Perhaps the wind caused the dust to enter the homes as well, and there was thus no escape from it. This is a correct [conjecture]. Many times during a drought, the fall of the dew is accompanied by a sort of dust, and it is furthermore written, The Eternal will make the rain of thy land powder and dust.²⁰⁵Deuteronomy 28:24.
It is also possible to say, in line with the plain meaning of Scripture, that the purport of the expression, And it shall become small dust, is that the dust which will be produced in that place from the soot will bring the boils over all the land of Egypt, as He infected the air to do so, it being a decree of the Supreme One.²⁰⁶According to this interpretation, the miracle entailed was thus greater than the one in consonance with the first interpretation, which had the dust throughout the land of Egypt causing the boils and the blains. According to the second interpretation, the soot of the furnace became dust only over the place where the miracle was wrought, which in turn caused the whole atmosphere over Egypt to effect the boils.

פורח, chemically active, producing spontaneous growth of bacteria.

והיה לאבק, “it will turn into dust.” According to our sages this minute amount of furnace dust scattered over the entire land of Egypt and descended wherever there was a human being or beast that it could land on, and these would break out in painful boils on their skin. Perhaps the wind carried this dust even into the houses of the Egyptians. A similar phenomenon is well known as occurring during periods of drought when dust is brought even into the houses with the nightly dew. Perhaps a straightforward explanation of the verse is that the words והיה לאבק, “it will turn into dust,” means that this soot from the furnace will immediately be turned into dust that in turn would turn into boils the moment Moses and Aaron threw it into the air. G’d decreed that this soot [normally the antithesis of anything septic. Ed.] will pollute the air and spread this painful series of boils. This was a heavenly decree not accounted for by any of the scientists.

Meaning of heat. [Rashi explains this] because the verse implies that the rash [itself] caused the boils, which is incorrect. Therefore Rashi says that שחין “has the meaning of heat,” and the boils were caused by the heat.

לאבק “into dust;” the letter ל has the semi vowel sheva, whereas the letter א has the vowel kametz.

שחין has the meaning of “heat”. In the Mishnaic Hebrew there are many examples of its use; e. g., (Yoma 53b) “a hot (שחונה) year”.