Why did the stick turn specifically into a snake?
Rashi and Ramban 1 : It was Midah Keneged Midah, because, by speaking Lashon ha'Ra against Yisrael, Moshe adopted the 'profession' of the snake, who was the first to speak Lashon ha'Ra. 2
Da'as Zekenim, Hadar Zekenim (to 4:2): Just like a snake bites and kills, so Pharaoh and his servants bite and kill Yisrael. 3
See Bereishis 3:4-5. Also see Rashi to Shemos 4:6.
Da'as Zekenim, Hadar Zekenim (to 4:2,3): It turned back into a staff, to demonstrate that Pharaoh and his servants will become like dry wood. The Tzara'as hinted that Pharaoh and his servants would be Tamei and be Metamei Yisrael. His hand returned to normal, to hint that Yisrael will be purified from the Tum'ah of Egypt.
Why did Moshe run away from a wooden snake?
Seforno: The snake that the stick turned into was a live one. 1
Seeing as Moshe did not doubt that it was Hashem who was speaking to him, why did Hashem perform these wonders in front of him?
Ramban #1: It was Midah Keneged Midah, 1 because Moshe spoke Lashon ha'Ra against Yisrael. The first sign came as a hint; the second, as a punishment. 2
According to Maharal, what meaning is contained within this series of three signs (4:3-9)?
Maharal #1 (Gevuros Hashem Ch. 27, p. 110): The three signs allude to reasons that Yisrael was now being redeemed. a) The Egyptians were "biting" and killing them like a snake; c) they despised us as Tamei like a Metzora, and this was unbecoming for our true Kedushah; c) the blood hinted to the punishment awaiting the Egyptians for their deeds against us. 1
Maharal #2 (ibid.): The signs showed that Hashem rules over everything, and so His word must be heeded. When Hashem exacts punishment upon man; a) He first instills fear (as Moshe fled the snake), b) then He strikes him (e.g. Moshe's hand with Tzara'as), c) ultimately with a death-blow (e.g. to the Mitzrim, when the Nile turned to blood).
Maharal #3 (ibid.): The three signs reflect the three Avos. a) The snake's burning venom alludes to Yitzchak; b) Tzara'as white as snow (which is water) alludes to Avraham (whose trait is Chesed); 2 c) blood is hot like fire, and moist like water. Thus, it is the median between the two, representing Yaakov. 3 Additionally, blood represents a person's essence; this too is Yaakov's trait. 4
Expanding upon this, the Redemption would come; a) due to the Egyptians, to stop them from killing us; b) because the Tamei and the Tahor cannot co-exist; c) because Hashem had already promised to judge Egypt (Bereishis 15:14). (EK)
Maharal (Chidushei Agados Vol. 2, p. 22, to Nedarim 64b): Tzara'as is deficiency in the Guf, conceptualized at the right. The trait of Chesed is also associated with the right side.
(Abraham's trait is Chesed, which is symbolized by water; Yitzchak's trait is Din, symbolized by fire.) Yaakov's trait is Rachamim, the median of the two; so it is symbolized by blood. (Compare to Maharal (Nesivos Olam, Nesiv ha'Torah Ch. 2) - Milk (produced by [the mother's] blood) is the median between water and wine.)
"Blood is life" (Devarim 12:23). See Maharal (Gevuros Hashem Ch. 67, p. 312) - It was Yaakov, specifically, who had complete Tzelem Elokim; due to his Kedushah, he resembled Adam ha'Rishon in his very essence. Also refer to Bereishis 32:32:151.1:1 and its note. Maharal (Derech Chayim p. 247, to Avos 5:9) - Yaakov was the antithesis of (Esav's) bloodshed; also refer to Bereishis 49:3:2.1:1.
According to Maharal, how did each sign add upon the one that preceded it (see Rashi to 4:8)?
Maharal #1 (Gevuros Hashem Ch. 27, p. 111); Gur Aryeh (to 4:9): Each miracle was greater than the previous one. a) The staff turning into a snake was not an absolute change, for even then, it had to change back to a staff as it was before. (After all, this was the unique "Mateh of G-d" (4:20)!) b) The Tzara'as on Moshe's hand was a true organic change, like any Tzara'as, yet it did not remain that way; it changed back to its normal state. c) The water became absolute blood, and it did not revert back at all. 1
Maharal #2 (ibid.): The signs included elements of both fire (i.e. venom) and water (snow), which are opposing forces. One who did not believe the veracity of the first miracle, would have to believe the second. If not, the third sign was the combination of the prior two (refer to 4:3:3.1:3).
Compare to Maharal (Gevuros Hashem loc. cit.) - All Tzara'as eventually fades away and heals, such that the change in Moshe's hand was not absolute. The water changing to blood was absolute and non- reversible.
QUESTIONS ON RASHI
Rashi writes: "Hashem hinted that in [Moshe] speaking Lashon ha'Ra about Yisrael, he had taken up the craft of the snake." Why is Lashon ha'Ra associated specifically with the snake?
Maharal (Nesivos Olam, Nesiv ha'Lashon, end Ch. 3, p. 70): A snake bites only out of a desire to do harm; he gets no benefit from the result. 1 This goes against to the normal natural order. So too, one who spreads Lashon ha'Ra has no tangible benefit from doing so. 2
For why should a snake bite a person (or any large animal); can it swallow him whole?! (CS)
Maharal (ibid.): A snake lives apart from other creatures, and there is enmity between it and man (Bereishis 3:15). Likewise, the talebearer desires doing harm; and all shun him. Also see Maharal (Nesivos Olam, Nesiv ha'Avodah Ch. 10, p. 108).
