Post: In Birkas Avraham on Vaera:
"5. An explanation of the symbol psik (a vertical bar | ) after the words הנה אנכי מכה, and between the phrase ויעשו כן משה ואהרן כאשר and the phrase צוה השם.
In the pasuk (Shemot 7:16-20)... there is the symbol of psik (a vertical bar | ) in pasuk 17 after the words הנה אנכי מכה. And also in pasuk 20, after the words ויעשו כן משה ואהרן כאשר, there is the symbol of psik.
And perhaps this is because in the beginning of the speech in this matter, Moshe Rabeinu said to Pharaoh (in 7:17) 'Behold I will hit with the staff which is in my hand', and this is that he, himself, would hit. And after that it is stated from Hashem Yisbarach (in 7:19) that Aharon will be the one who hits.
And also for this is needed a psik in pasuk 20, after the word כאשר, for the smiting via the hand of Aharon is not like the language that Moshe Rabbenu said to Pharaoh in the beginning of the matter."
You already know my take on this. Neither of these is a true psik. They are orthographically identical, but each is really a munach legarmeih. Besides this, it feels forced. He does not explain precisely how the psik helps in each location, and why precisely a psik is appropriate.
Still, one can answer the difficulties, and I like to take note of trup-oriented divrei Torah on the parsha.
Regardless, the variance between what Moshe told Pharaoh he would do and what actually occurred in intriguing. Indeed, Rashi (and Tanchuma recognize this):
|Say to Aaron: Since the Nile protected Moses when he was cast into it, it therefore was not smitten by him, neither with blood nor with frogs, but was smitten by Aaron. — [from Tanchuma, Va’era 14]||אמר אל אהרן: לפי שהגין היאור על משה כשנשלך לתוכו, לפיכך לא לקה על ידו לא בדם ולא בצפרדעים, ולקה על ידי אהרן:|
I would guess that it is not just that Aharon did this (and other events where there was cause for hakaras hatov), but that it is slightly at odds with a strict reading of the earlier description.
The Documentary Hypothesis resolves the issue by assigning the end halves (!) of pasuk 15, 16, 17, and 20 to E, and pasuk 19 and the beginning part of 20 to J. That way, in one text, Moshe does it, and in another, Aharon does it. I don't generally subscribe to the DH, but this seems more farfetched than usual. Still, by dividing the text into enough pieces, we do manage to eliminate conflicts.
I am not sure if Ibn Ezra grapples with this issue as well. He writes:
[ז, יז]And Ibn Caspi writes:
כה -השליח ידבר על פי השולח ואמר דרך קצרה, כי תחסר מלת שלוחו. וככה הנה אנכי שלוחו מכה במטה אשר בידי.
ואמר אשר בידי ואע"פ שביד אהרן היה. כי שניהם שוים ומשתתפים באות.
הנה אנכי מכה . כינוי לשם ג"כ, כי הוא המכה במטה
אשר בידו ואם אינו הקרוב, וגם נכון שיתחיל משה לדבר בעד עצמו
כאמרו הנה אנכי וכו'ש
I don't think that they are addressing this issue per se. It seems more that they are addressing anochi which is the act of Moshe/Aharon, when this was preceded by a ko amar Hashem, and a ki ani Hashem. Thus, why the shift to Moshe as actor as as anochi. So, it can refer to Hashem as well; or Moshe suddenly grabbed the anochi to refer to himself.
However, according to Ibn Ezra and Ibn Caspi that the actor is Hashem who is smiting (rather than striking with a staff) the water, there is no contradiction with the later action by Aharon as opposed to Moshe.