Комментарий к Шмот 8:13

ותהי הכנם means the swarming was. In old French pedulier.

הכנם. The final letter ם is similar to the final letter ם in the word ריקם in Genesis 31,42 where it is not really required, [the exegesis is needed as the author considered the same final latter in the word לכנם in the previous verse as a plural ending. Ed.]

ותהי הכנם באדם, the insects remained on man, etc. We would have expected the Torah to say: כל עפר הארץ היה כנים, ותהי הכנים באדם "the whole dust of the earth turned into insects, and the insects remained on man, etc." Why did the Torah reverse this sequence by telling us first that the insects remained on man? We may understand this with the help of an argument between Rabbi Yoseph from Orleans and Rabbenu Tam cited on Shabbat 12 concerning the meaning of the word כנה. Some rabbis hold that what is meant is a black flea, an insect which originated in the dust and which is able to jump very high. Other rabbis hold that these "insects" were white parasites which originated on the clothes people wore. These rabbis prove their point by basing themselves on a statement in Berachot 51 according to which vermin is generated from rags. In order to prevent the reader from making the error that the כנה described here is the so-called כנה לבנה, the parasite, the Torah makes the point that it originated from the dust of the earth. Had the Torah used the version commencing with the words: כל עפר הארץ היה כנים, there could have been no question about the insects originating in the earth. The Torah therefore displayed wisdom by writing ותהי הכנם באדם, to tell us that the insects which were normally generated in dirty clothes now became a plague of intolerable dimensions so that both man and animal suffered from an excessive amount of fleas, etc., each of the variety they were familiar with.

ויעשו כן, “they did so.” Even though the command was executed only by Aaron, the Torah includes the issuance of the command by Moses, and that is why it uses the plural mode when describing its execution.

V. 13. Schmarotzertiere, כנים, kriechen sonst nicht an Tiere hinan, sondern entstehen an und auf ihnen. Nicht so hier. Der Erdenstaub ward zu כנים und sie krochen an Menschen und Tiere. Auch dies war gegen die sonstige Ordnung der Natur. In dieser Strafplage konzentrieren sich גרות und עבדות in schmerzhaft fühlbarer Weise. Mizrajim hätte fort müssen, wenn ihr Boden — der sonstige Stolz ihrer Existenz — dauernd in כנים umwandelt bliebe, und ohne Scheu krochen die lästigen Tiere an die hochmütigen Herren hinauf.

It is also possible that the Torah speaks about both variants of insects. The first category is alluded to in the words: ותהי הכנם באדם ובבהמה, meaning the varieties of parasites man and beast experience on their skin from time to time. This was in addition to the insects which originate in the earth and which are called כנים as distinct from the first variety which is called כנם. If this is correct, our verse does not serve as support for the opinion of Rabbi Yoseph from Orleans, and we would have to accept the view of Rabbenu Tam who proved in the Talmud that the insect known as the white one is a parasite, whereas the other one known as the black one, which is distinguished by its great jumps, is incorrectly referred to as כנה but is in reality a פרעוש. (This is also the ruling of the halachah compare Tur Shulchan Aruch, Or Hachayim ruling 315).