שמות, פרק ד׳, פסוק ט׳

As Moses prepares for his monumental mission to Egypt, God arms him with an escalating series of supernatural proofs. The third sign given to him is not merely another method of persuasion, but an absolute demonstration of power designed to strike at the very foundation of the Egyptian empire while addressing the deepest layers of doubt among the Israelites.

God introduces this sign to calm the psychological fears Moses harbors. Even if the Israelites witness the first two signs and show no open lack of faith, God knows Moses might still worry that they secretly harbor doubts. This third act is meant to uproot that hidden skepticism entirely [אור החיים, קאסוטו]. Unlike the initial wonders performed immediately at the burning bush, this one cannot be tested on the spot because it requires water from the Nile. Instead, God promises Moses that the miracle will occur when the time comes in Egypt [ביאור שטיינזלץ].

The act also serves as a stark warning to those with little faith who might later deny Moses when the harshness of slavery intensifies. It illustrates how the process of redemption, compared to living water, can transform into a deadly poison for those who refuse to believe and avoid sharing in the suffering of the community [העמק דבר, מלבי״ם].

Taking water from the Nile carries immense symbolic weight. The river is the source of life, agriculture, and wealth for Egypt, revered by them as an actual deity. Striking it proves that God holds absolute control over nature and the Egyptian gods, effectively serving as a preview of the first of the Ten Plagues [רש״י, אבן עזרא, כלי יקר, רש״ר הירש, קאסוטו]. Furthermore, the transformation of water into blood hints at the future punishment awaiting the Egyptians. The spilling of their blood during the plague of the firstborn and the splitting of the sea acts as a direct, measure for measure retribution for casting Israelite infants into the river [הדר זקנים, דעת זקנים, חתם סופר].

This sign differs fundamentally from the earlier wonders. While the staff and the diseased hand eventually return to their natural states, turning water into blood is a permanent, essential alteration of a simple substance into a complex one. This irreversible change proves beyond any doubt that the event is an act of God's might, rather than mere illusion or sorcery, which typically reverts to its original form [ספורנו, חזקוני, מלבי״ם, גור אריה].

A unique repetition in the phrasing of the command reveals crucial details about how the miracle unfolds. The primary approach among commentators explains that the repetition highlights the precise timing of the wonder. The water remains perfectly pure while held in Moses' hand and transforms into blood only at the exact moment it strikes the dry ground. This pinpoint accuracy prevents skeptics from claiming that Moses secretly held dye or a magical substance in his palm [רש״י, רבינו בחיי, מלבי״ם, לבוש האורה, דברי דוד]. Another perspective suggests the delay occurs so that Moses does not directly strike or harm the water of the Nile, showing gratitude to the river that protected him when he was a baby in the basket [אור החיים]. Others view the repeated phrasing as proof that the water undergoes a permanent physical change, or that the miracle will repeat itself whenever the people demand to test Moses [גור אריה, יריעות שלמה, העמק דבר]. Conversely, some scholars argue against finding hidden meaning in the repetition. They explain that according to biblical grammar, repeating a word is simply a common stylistic choice used for emphasis or to connect the parts of a long sentence [רמב״ן, רשב״ם, שפתי חכמים].