Exodus 7:17Meaning & Commentary from the Church Fathers

As Moses observed that those under his authority shared the mindset of the leader of darkness, he struck a decisive blow against the entire Egyptian nation, without sparing anyone in distress. In this assault on the Egyptians, all elements of creation—earth, fire, air, and water—responded, altering their natural functions according to the will of men. With one singular force, through synchronized action in one location, chaos was confronted, and those who remained undisturbed were free from transgression. By Moses’ command, all the water in Egypt was transformed into blood, leading to the corruption of the fish due to this shift from water to a fleshly substance.

Observe (Exodus 7:20) Thus, he predicts the judgments, so that they do not think these events occur randomly, but rather acknowledge them as decrees from the Lord.

Moses' initial signs featured blood, and this theme of water recurs at the conclusion of Jesus' signs. Initially, Moses transformed the river into blood; likewise, Jesus, at the end of His earthly journey, poured forth both water and blood from His side, possibly symbolizing two distinct cries: the proclamation of the Judge and the pleas of those who seek Him, or perhaps the voices of the faithful and the unfaithful (John 19:34).

Certain biblical scholars, in an attempt to explain this miracle as a simple natural occurrence routinely seen in Egypt during June, when the Nile swells, and in October, when it retreats, suggest that the annual reddening of the Nile's waters arises from a combination of the red soil of Ethiopia that the river traverses, the vibrant hues of the sands carried by southern winds, and predominantly from a unique species of red infusoria. Cook, referencing Ehrenberg, notes that during periods of high water, a significant population of red infusoria blooms, turning the water a vivid red. The frequency of these organisms varies annually, as does their appearance throughout the season. However, typically, these infusoria do not result in the death of fish in the Nile.