What does Exodus 10:22 mean?
The description here uses two Hebrew root words for emphasis. One is apēlāh, the other is hōsek. Both refer to darkness in different ways. This resembles English expressions such as "pitch black" or "jet black," as pitch and jet are both materials noted for their deep, dark, black color. All of these phrases are meant to mean "as dark as possible." Many interpreters take this to mean that the ninth plague on Egypt (Exodus 7:21; 8:6, 17, 24; 9:6, 10, 24; 10:14) supernaturally blocks light and every person is blinded (Exodus 10:23).At the same time, the expressions used here may not be absolutely literal. Sandstorms and other conditions can block virtually all light from the sun. One of the recent disasters was a vicious storm of hail and lightning (Exodus 9:23–25). It may be that things like torches and lamps still worked, but the people were terrified to leave their homes for fear of what was happening.
Either way, this makes a direct attack on ancient Egyptian religion. Ra, the Egyptian sun god, supposedly had power over such things. This disaster proves this to be untrue. To make the point even clearer, territory settled by Hebrew slaves has plenty of light. This is another explicit distinction made around God's people (Exodus 8:22; 9:4, 7, 26). Egypt has held the Israelites as slaves (Exodus 1:11–14) and they are now paying the price. Their king has been commanded to release the Hebrews (Exodus 5:1; 7:16; 8:1, 21; 9:1, 13; 10:3). He has been obstinate (Exodus 5:2; 7:13–14, 22; 8:15, 19, 32; 9:7, 35; 10:20).