שמות, פרק ז׳, פסוק כ׳

The climax of the first plague arrives as God’s warning materializes, transforming the nature of Egypt's waters before the eyes of its entire leadership. Executing this dramatic event involved a specific division of roles. The primary approach among commentators is that Moses was responsible for speaking and delivering the warning, while Aaron acted as his agent, physically lifting the staff and striking the Nile [רשב״ם, הכתב והקבלה, מלבי״ם, ביאור יש״ר, שטיינזלץ]. However, others suggest that Moses himself struck the water [קאסוטו], or that the act was performed with Moses' famous staff, but God Himself, so to speak, lifted it [העמק דבר]. The action aligned perfectly with the Divine will, as if God Himself had directly ordered the river to turn into blood [אור החיים]. This perfect alignment also hints at an additional oral command given to Moses to stretch out his hand [העמק דבר].

Although the physical act of striking was directed at the Nile, the plague encompassed all water sources. Lifting the staff involved stretching a hand in every direction across the entire land of Egypt [רמב״ן, הטור הארוך]. The Nile is highlighted specifically because it was the central and most vital river [הכתב והקבלה], and because striking it was the only action performed directly in front of Pharaoh, whereas the rest of the waters were struck outside his presence [אבן עזרא, מלבי״ם]. The event was highly public. Even though the morning meeting between Moses, Aaron, and Pharaoh began in private, the leaders intentionally waited for the king's servants to gather. This ensured the miracle would be performed publicly [אור החיים], a deliberate choice that also served to emphasize the honor of Moses [רשב״ם].

The transformation of the water was a completely supernatural event, dismissing any claims that it was merely a natural phenomenon of the river turning red. The water was fundamentally ruined and emitted a terrible stench that killed all the fish—a result not found in natural occurrences—proving to Pharaoh that God has absolute control over nature [שד״ל]. An interesting debate exists regarding how long the water remained blood. One perspective argues that the transformation lasted only for a brief moment. In that instant, the fish died, and the river immediately reverted to normal water. The Egyptians' inability to drink stemmed from the foul stench of the dead fish rather than the blood itself. This explains how the Egyptian magicians were able to turn water into blood right afterward, as the river had already returned to its natural state, and why Moses did not need to pray for the plague to end [בכור שור, חזקוני]. Conversely, another view suggests that the visible waters of the river remained blood for an extended period. Because of this, the magicians were forced to dig for hidden groundwater to perform their magic, as only the water beneath the earth's surface escaped the plague [חזקוני].