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Why Did Moses Not Bring a Plague on the Nile

Prof. Daniel Sperber
Department of Talmud

With respect to Exodus 7:19 - "And the Lord said to Moses, 'Say to Aaron: Take your rod and hold out your arm over the waters of Egypt - its rivers, its canals its ponds, all its bodies of water - that they may turn to blood; there shall be blood throughout the land of Egypt, even in vessels of wood and stone'" - Rashi notes: "Aaron was told [to do this] since it had been the Nile that protected Moses when he was cast into it; therefore neither the blood nor the frogs were brought on my him, rather they were brought on by Aaron."

This idea can be found in Exodus Rabbah 20.1:

The Holy One, blessed be He, began saying to Moses, "Tell Pharaoh to let my people go that they may worship Me." So he went and told him. He [Pharaoh] began by responding, "Who is the Lord, that I should listen to him?"´ Moses began saying to the Holy One, blessed be He, "Behold, he says, 'Who is the Lord?' and he does not want to let them go." The Lord answered him [Moses]: "Where do the Egyptians get their water to drink?" Moses answered, "From the Nile." The Lord said to him, "Turn it into blood." Moses replied, "I cannot do so. Does a person who drinks water from a well throw a stone into it?!" The Lord said, "Let Aaron go and turn it to blood." So Aaron went and struck the Nile, and it turned to blood. And why did Moses not strike it? He said: "I was thrown into it, and it did not harm me." Therefore, Aaron struck it.

A similar midrashic interpretation of Numbers 31:1-2 appears in Numbers Rabbah:

"The Lord spoke to Moses, saying, 'Avenge the Israelite people on the Midianites; then you shall be gathered to your kin.'" The Holy One, blessed be He, said to Moses: "Avenge," you yourself. But Moses dispatched others [to do this] (for in verse 3 it says, "Moses spoke to the people, saying, 'Let men be picked out from among you for a campaign, ... to wreak the Lord's vengeance on Midian," and in verse 6 it says, "Moses dispatched them"). The reason was that he had grown up in the land of Midian and said, "It is not right that I should cause misfortune to those who did me well: into the well from which you drank, do not cast a stone.

A slightly variant form of this homily appears in Midrash Ha-Gadol on Exodus 7:19-20. The midrash cites in the name of R. Tanhum as follows: "As people say, into a well from which you drank, do not throw in a stone." (Another variant appears in Midrash Ha-Gadol on Exodus 16:8, but not from R. Tanhum, for it does not appear in Tanhuma Va-Era 14 or in Mishnat R. Eliezer, Ch. 19ff). A slightly different form of this saying can be found in Bava Kama 42a, in the name of Rabba. Kala, the word which we have rendered as "stone," could also mean a clod of earth, etc.[1] The basic idea of this folk saying is that one should not hurt a person or thing that has helped or brought benefit to oneself. This is such a simple idea that it is not surprising it appears as a folk saying in many cultures. For example, in late Egyptian demotic wisdom literature, the proverbs of Ankhashshonki [SP?] contain the following saying: Do not drink water from a well and then throw your jug into it.[2] The original Jewish saying even found its way into 15th-16th century English literature.[3] Jon Ray cites the following saying from a source entitled Adagia Hebraica: "Never cast dirt into the fountain of which you sometimes drank." Similar sayings can be found in J. Mapletoft, Select Proverbs, 1707, and in F. Fuller's Gnomologia, 1732. Even Shakespeare wrote in The Rope of Lucrece, line 577, dated 1593-1594: "Mud not the fountain that gave drink to you."[4] His source may well have been the same Adagia Hebraica mentioned above.

On the one hand, clearly one or more plagues would have to be brought against the Nile, since it was one of the Egyptians' more important deities, known as Nilus and also as Khappi,[5] as it is written (Ex. 12:12): "and I will mete out punishments to all the gods of Egypt." On the other hand, Moses, who was saved by the water of the Nile, could not himself cause it harm, and therefore implementation of the plague was entrusted to Aaron, therefore it was he who struck the Nile using Moses' staff.

[1] Cf. Tosafot he-Arukh ha-Shalem, ed. S. Krause, p. 361, under q-l-a, apparently related to the Syriac qula'a, meaning a clod of earth, clay, etc.
[2] Miriam Lichtheim, Late Egyptian Wisdom Literature in the International Context: Study of Demotic Instructions, Gottingen 1983, p. 30. Cf. Stricker in Oudheidkundige Medeleelirgen uit het Rijksmuseum Oudheden te, Leiden, v. 50, p. 18. In Greek literature this saying takes on a different meaning (cf. Plutarch, Questiones Convivalen, Part IV, 703): "It is a sin to destroy food of which we have partaken, or to conceal a spring as soon as we have quenched our thirst" (cf. Lichtheim, loc. sit.). Also see Shabbat 66b: "Rav Aha said to him ... let him take a fresh jug down to the river and say: River, river, lend me a jug of water for the guest who has come to visit me. And let him twirl the jug on his head seven times, and spill it out behind him, and say: River, river, take back the water that you gave me, for my guest has come and gone it a trice. But let him not cast the jug into the river."
[3] Jon Ray, A Collection of English Proverbs not Known Generally, 1678.
[4] Cf. Titus Andronicus. See M. P. Tillery, Dictionary of Proverbs in England in the Sixteenth and Seventeenth Centuries, Michigan University, 1966, p. 157.
[5] Cf. S. W. Shorter, The Egyptian Gods: A Handbook, London 1937, pp. 103, 130, on this deity.