Understand the air in the same way: through the staff it becomes dark before the eyes of the Egyptians, while for the Hebrews it shines with sunlight. This especially confirms the interpretation we have given. No coercive power from above makes one person live in darkness and another in light. We human beings possess within our own nature and free choice the causes of light and darkness, and we become whichever of the two we choose.
For in the story there was no wall or mountain blocking the view and cutting off the rays so that the Hebrews could enjoy the light while the Egyptians remained unaware of its grace. In the same way, the life of light is set equally before everyone and lies within our power. Some travel through darkness, driven by evil practices into the gloom of vice, while others are made radiant by the light of virtue.
If, after suffering for three days in darkness, the Egyptians also come to share in the light, one might take this as an image of those who formerly lived as Egyptians but pass from vice to virtue through knowledge of the Crucified and through repentance. That palpable darkness, as the story calls it, has a close kinship in both name and meaning with the darkness of ignorance and sin. Both kinds of darkness are dissolved when Moses stretches out his hands over those in darkness, as we understood in the preceding passage.
The ashes from the furnace that bring painful blisters upon the Egyptians can likewise be understood, through the image contained in the word “furnace,” as the punishment by fire threatened in Gehenna. It touches only those who live as Egyptians—that is, as we have often said, those who live wickedly and do not worship the outstretched hands of Christ.
But anyone who is truly an Israelite, a son of Abraham, and looks to him in his way of life so as to show by free choice his kinship with the elect is preserved from that pain of the furnace. And for those others too, the interpretation we have given of Moses’ outstretched hands may someday become a healing of their pain and a release from punishment.
There are also the tiny gnats that hurt the Egyptians with unseen bites and the biting flies that painfully fasten themselves to their bodies. Then there are the crops destroyed by locusts and the lightning storms that fall from above with hailstones. Anyone who follows the sequence of what we have already examined should have little difficulty fitting each of these to an appropriate interpretation.
In the primary sense, all these things are produced by the Egyptian choice, while the impartial justice of God brings the consequences upon it. Following this reasoning, we can say that painful consequences come from God upon those who deserve them, while also understanding that each person becomes the creator of his own plagues by preparing through his own choice the conditions for his suffering. As the Apostle says to such a person: “According to your hardness and unrepentant heart, you are storing up wrath for yourself on the day of wrath and of the revelation and righteous judgment of God, who will repay each person according to his works.”
Consider a bodily analogy. A disorderly diet may produce a corrupt and bilious fluid in the body. If a physician uses his skill to draw it out by vomiting, no one blames the physician for having produced the diseased fluid in the body. The disorderly diet produced it; medical skill merely brought it into the open. In the same way, even when painful retribution is said to come from God upon those whose choice is evil, it is reasonable to understand such sufferings as taking their beginnings and causes from ourselves.
For the person who has lived without sin there is no darkness, no worm, no Gehenna, no fire, and none of the other fearful names or realities. So too the story says that the Egyptian plagues did not fall upon the Hebrews. If the same thing is an evil for one person but not for another under the same circumstances, the difference comes from their choices. Each choice produces its corresponding result. It is therefore clear that none of these evils can arise apart from our own free choice.