Comentário sobre Êxodo 8:12

אמר אל אהרן SAY UNTO AARON — The dust did not deserve to be smitten by Moses because it had protected him when he slew the Egyptian, for “he hid him in the sand”; and it was therefore smitten by Aaron (Tanchuma; Exodus Rabbah 10:7).

לכנם, different kinds of insects that cause man discomfort.

והך את עפר הארץ, they did not warn Pharaoh of the advent of this plague. Neither did they warn him before the onset of the שחין, the boils and blisters, nor before the darkness. The nine plagues, exclusive of the killing of the firstborn, were intended to serve as demonstrations of G’d’s power to change the laws of nature. Although the simultaneous dying of the firstborn was also a powerful such demonstration, it was intended as retribution for refusal to heed all the warnings G’d had extended to Pharaoh and his people. The first 3 plagues דצ'ך, demonstrated mastery of G’d over the two “heavy” components of the four basic elements the universe is made of, i.e. water and earth, The three plagues, abbreviated under the heading of עד'ש by Rabbi Yehudah Hanassi, demonstrates G’d’s control not only over inert parts of nature but also over living creatures. The third category בא'ח, demonstrated G’d complete control of the air, the atmosphere including the other two basic elements known as רוח and אש, air, wind, and fire. In each group the first two plagues were preceded by warnings, whereas the third was not. The matter has been alluded to in Job 33,29 הן כל אלה יפעל א-ל, פעמים שלוש עם גבר. “Truly, G’d does all these things, two or three times to a man.”