Kommentar zu Schemot 7:20

AND HE LIFTED UP THE ROD, AND SMOTE THE WATERS THAT WERE IN THE RIVER IN THE SIGHT OF PHARAOH. That is to say, Aaron lifted up the rod and stretched out his hand over the land of Egypt in all directions,¹²⁵Ramban’s intent is to state that the lifting up of the rod, mentioned here in Verse 20, is identical with “stretch out thy hand,” mentioned in G-d’s command in Verse 19. Ibn Ezra, as stated further in the text, differs with this opinion. and afterwards he smote the waters that were in the river, in the sight of Pharaoh. In Pharaoh’s sight, all the waters that were in the river turned to blood, and the blood was furthermore throughout all the land of Egypt.¹²⁶Verse 21. Ramban thus explains that the waters that were in the river turned to blood by reason of the smiting of the rod, while the waters in all other places turned into blood by reason of Aaron’s stretching forth his hand in all directions (Bachya). And Rabbi Abraham ibn Ezra said that Scripture mentioned the smiting of the river but found it unnecessary to mention the stretching out of the hand [in all directions] over the entire land of Egypt.¹²⁷Thus according to Ibn Ezra, Scripture merely shortened its account here and did not mention the stretching out of Aaron’s hand, but not, as Ramban has it, that the stretching out of the hand is already included in the act of the smiting of the waters of the river.

לעיני פרעה, this was a big boost for Moses’ stature, that Aaron, merely his messenger, was able to accomplish this and use his staff on a regular basis.

ויעשו כן משה ואהרן, Moses and Aaron did so precisely, etc. This means that when Moses and Aaron smote the river the result was that G'd's will was done and the result was the same as if G'd Himself had struck the river. Please read what I have already written on verse six concerning such expressions in the Torah, as well as what I shall be writing on the verse following.

וירם במטה, “he held the staff aloft, etc.” Nachmanides explains the construction וירם במטה as meaning that Aaron raised the staff with his hand extending it in all the directions of the globe, exactly as commanded, i.e. קח את מטך ונטה את ידך, and after having extended his hand in every direction he proceeded to strike the waters of the river Nile. Ibn Ezra also writes that the Torah mentions the fact that the river was struck, but there was no need to mention the motions made with the hand or arm in all directions of the land of Egypt, as the raising of the staff automatically includes the raising of the hand holding the staff.

ויהפכו כל המים אשר ביאור לדם, “all the water in the river had been turned into blood.” The river had been turned into blood only temporarily, and the fish died immediately on account of being unable to survive in a river of blood. As soon as all the fish had died, the river reverted to being water. As to the Torah having written that “the Egyptians could not drink water from the river,” this was not on account of the blood, for we do not find that they even tried to reverse the plague, but that was, as the Torah writes, because the stench of the water on account of all the dead fish. The proof of this is that the Torah writes: ויעשו כן כל חרטומי מצרים, “all of the sorcerers of Egypt performed a similar miracle;” if the waters had not first been restored, how could they have demonstrated their sorcery? Some commentators claim that the plague lasted for slightly over a week, a quarter of a month, for all waters visible to the people during that period. During that period, the sorcerers busied themselves with subterranean water. Their proof is that the Torah writes that “the Egyptians dug all around the river to find water as they could not drink the water from the river.” (verse 24). The subterranean waters had not been turned into blood.

לעיני פרעה ולעיני עבדיו, before the eyes of Pharaoh and the eyes of his servants. Although Moses issued the warning to Pharaoh when the latter was unaccompanied because he hid his need to answer calls of nature, the Torah tells us that G'd delayed implementing the plague until it could be done publicly in the presence of Pharaoh's servants. While it is true that the text does not mention this, it is most likely that G'd had mentioned this to Moses for reasons of maximum effect. It is even possible that the words כן כאשר צוה, "exactly as He commanded," refer to words G'd had told Moses but which were not spelled out in our text.