Why all this darkness? For light. This is a darkness that foreshadows. It foreshadows a greater darkness by which came the great light.
While there is darkness in Egypt light shines upon God’s people. God makes distinction. In covenant love He has chosen Israel. By this darkness, light is shed. By this darkness, the gospel is proclaimed.
Following this wonder, God again hardens Pharaoh’s heart. Why? For another darkness. A deeper darkness. Why? For greater light. God wanted to crest with the death of the firstborn (Exodus 4:21–23). This would be a darkness that not even His people were immune to. They were not immune, but they were provided a substitute. By this darkness, light is shed. By this darkness, the gospel is proclaimed.
On a dark night the disciples partook of the Passover. Jesus changed the liturgy to speak of His broken body and his spilled blood. During darkness, light is shed. During darkness, the gospel is proclaimed.
The next day the sky turned black as the substitute Lamb’s body was broken, as His blood was poured out to ransom His people. By that darkness, light is. By that darkness, the gospel is.
The ninth plague foreshadows. The light for the shadow casted came from the future, and that light came out of darkness. Three hours of darkness at the cross gave way to three days of darkness in the grave, but the Son rose on Resurrection morn as the Light to unfailing shine upon His people. Darkness for light and light by darkness.