Who is afraid of the dark? In the middle of the night, my daughter cries out for her parents, afraid of what lurks in the shadows. As a child, I remember lying in the dark at night in my grandparents’ basement, listening to the pipes clank, imagination aflame. Being alone in the dark brings out a primitive fear in many of us, a sense of isolation and abandonment. Every sound or movement is magnified because one of our senses, sight, is hindered. It is perhaps no wonder, then, that God uses the absence of light, the plague of darkness, to take the divine punishment of the Egyptians to a new level.

Parashat Bo tells the story of the last three plagues, as the Israelites slip from Pharaoh’s grasp into freedom. When the locusts fail to spring the Israelites from Egypt, God plunges the land into deep darkness. The details of the plague are sparse. It arrives unannounced, without a warning from Moses to Pharaoh. God commands Moses to bring about “a darkness that can be touched,” (Exodus 10:21) and for three days the Egyptians are paralyzed, unable to see one another, too terrified to move. Given the degree to which the plagues have been building in severity to this point, I have always been somewhat amazed that the plague of darkness, in all its simplicity, arrives so late in the game. Why is darkness so terrible? It doesn’t have the drama of the locusts, the raining terror of the hail, or the wailing and despair of the plague of the first-born. It is just dark – unimaginably dark – for three full days.

In her commentary on Exodus, Carol Meyers points out that the darkness is not totally unexpected, having been a component of other plagues. The locusts are so numerous to make it impossible for people to see (10:15), and both the death of the first born (12:29) and the crossing of the Sea of Reeds (14:20) take place in the middle of the night. The darkness also symbolizes chaos, a world without order, since in Genesis there is also darkness before God begins to create (Genesis 1:2). Meyers reminds us that to the Egyptians, who saw the sun god as the source of life, the darkness was a symbol of death, and it foreshadows the lethal final plague. By banishing light, God demonstrated total control over all that Egypt held sacred. The darkness was effective because the Egyptians literally believed that their world was coming to an end, with their gods vanquished.

The traditional commentators tried to make sense of the fact that the darkness gained substance, that it was “a darkness that could be touched.” Rashi described the darkness as thickening and expanding, growing in size until it became a darkness of matter. Ibn Ezra likened it to the extremely dense fog that would settle on the Atlantic Ocean for days at time, which he had experienced himself. And Nahmanides captured the sense of other-worldliness the darkness wrought by comparing it to the blackness of mines and other deep places where fires could not burn; otherwise the Egyptians could have just used lamps. Darkness may seem like a childish fear, but the true absence of light, without any recourse or way out, is terrifying.

One of the best descriptions I have ever seen of the terror of darkness is in Isaac Asimov’s 1941 short story “Nightfall,” which takes place on an alien world that is constantly illuminated by six suns. The constant sunlight means that neither stars nor moons are regularly visible, and the inhabitants of the planet never know what it is to be in full darkness. Indeed, one popular amusement park ride is a fifteen-minute journey through a completely black tunnel, which is shut down after 10 percent of riders are rendered insane from darkness-induced claustrophobia. The planet’s scientists discover to their horror that every several thousand years, there is a total solar eclipse, plunging the planet into darkness and causing the crazed inhabitants to burn down all the cities in an effort to create light. One of Asimov’s characters describes the sensation of eclipse: “For this was the Dark – the Dark and the Cold and the Doom. The bright walls of the universe were shattered and their awful black fragments were falling down to crush and squeeze and obliterate him.”

When I read these words, I imagine them running through the mind of the Egyptians during the plague. Having attacked their bodies and their property, God’s penultimate act is to make them feel that their world has come to an end. For the Israelites, however, the plague is not an end but a beginning. They have light during the plague, not darkness (10:23), which magnifies their status as God’s chosen. Jewish tradition even holds that the light followed them into Egyptian territory, with the light clinging to them as they moved about Egypt. As the Egyptians sat in terror in their homes, the Israelites could roam freely.

It was the first taste of the freedom to come.