Exodus 7:21Meaning & Commentary from the Church Fathers

Moses, observing that those under his guidance were united in spirit with the leader of iniquity, delivered a decisive blow to the entire Egyptian nation, without sparing any among the afflicted. In this confrontation with the Egyptians, as if they were a force commanded by another, even the very elements of creation—earth, fire, air, and water—altered their natural powers in accordance with human will. By a single, unified power, at once and in one place, chaos was met with punishment, while those who remained unscathed were exempt from sin. Through Moses’ command, all the waters of Egypt were transformed into blood, leading to the decay of fish due to this conversion of water into foulness; for the Hebrews experienced this blood as water.

The fish that once consumed the bodies of infants perished. This decree was issued solely out of fear that the fish would die in place of the firstborn. Since the Egyptians were not moved by the death of the fish, they ought to have been convinced by the striking down of the firstborn.

Aaron, in the presence of Pharaoh, transformed the waters of the river into blood. He lifted his rod and struck the waters before Pharaoh and his officials, and thus the entire river was turned into blood. The wise men of Egypt, through their craftiness and sorcery, mimicked this act, as recorded in Scripture. It is written that the magicians of Egypt performed a similar feat using their enchantments. Given the remarkable nature of these events, one might consider whether the transformation of the river water into blood by Moses and Aaron was truly miraculous.