출애굽기 7:9 해설: Rashi, Chizkuni, Da'at Zekenim & Kli Yakar

מופת A WONDER — a sign to prove that there is power in Him who is sending you.

תנו לכם מופת,”perform a miracle in order to legitimize yourselves!” According to Rashi, the word מופת refers to a miracle that would prove who it is that authorised Moses to become the redeemer of the Israelites. G-d would have to demonstrate not only being a Ruler, but also His capacity to enforce his decrees. We have a source for this Rashi in Devarim Rabbah 2,11, which while not exactly what Rashi says nevertheless approximates it. Basically, it explains why paganism in Jewish literature is called עבודת כוכבים אלהים, literally: “worshiping stars as gods,” the reason being that [(my choice of words), “G-d is indispensable in our universe.” Otherwise, the word elohim in that expression is superfluous. Ed.] Rabbi Yossi claims that these deities cannot be called elohim, for if they were, it would follow that such a force must be obeyed. This is why the Torah in Deuteronomy 32,17, quotes Moses as referring to these so called deities as שדים לא אלוה, “satyrs, non deities.” Onkelos translates it as “something that is misleading,” as there is absolutely no need for it. For if there had been a need for such phenomena why would G-d be jealous of them?”

יהי לתנין “it will turn into a serpent.” Seeing that Pharaoh had proclaimed himself as equivalent to a giant monster, G–d was going to show him Who it was that created such monsters. (Compare Ezekiel 29,3.) The principal feature of serpents is that they bend and twist, so Pharaoh would also be forced to bend and twist. (Sh’mot Rabbah 9,4) He also afflicted him with the plague of tzoraat, (Exodus 11,1) reminding him that he should have learned a lesson from what happened to the first Pharaoh when he tried to rape the wife of the first Hebrew, Avraham (Genesis 12,17).