Read: Exodus 10-12
Marked: Exodus 10:21-23, Then the LORD said to Moses, “Stretch out your hand toward heaven, that there may be darkness over the land of Egypt, darkness [which] may even be felt.” So Moses stretched out his hand toward heaven, and there was thick darkness in all the land of Egypt three days. They did not see one another; nor did anyone rise from his place for three days. But all the children of Israel had light in their dwellings.
Metaphorically, the world is in darkness but doesn’t know it. It must have been terrifying for the Egyptians when darkness, a darkness which could be felt, came on Egypt for three days and the only light was in the dwellings of the children of Israel.
John chapter 1 tells us that Jesus is the light of men and that light shines in the darkness but the darkness didn’t comprehend it (V4-5). Darkness is oppressive, condemning, and John 3:19 says that when we reject the light of the love of God in Jesus we love darkness more.
You can get comfortable in the dark and not even realize it. I read once of cave explorers finding small fish and other creatures in the deepest darkest reaches of caves. These creatures had become so comfortable in the utter lack of light of their environment that, over time, they no longer needed their eyes and became blind.
Jesus has come to give light to the blind man and take us from darkness into the light (Luke 4:18; John 8:12).