Darkness" is a state without light. "Light" is truth from the Lord, so "darkness" represents a state where truth is lacking. Here's a cogent passage from Arcana Coelestia: "The person who has yet to be regenerated is called 'a void and an empty earth', and also 'ground', in which no good or truth at all has been sown - 'void' where there is no good, and 'empty' where there is no truth. Consequently there is 'thick darkness', or stupidity and lack of knowledge about anything that has to do with faith in the Lord and so anything that has to do with spiritual and celestial life. (Arcana Coelestia 17)
Matthew 27:3-6
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Then Judas, who betrayed him, when he saw that Jesus was condemned, felt remorse, and brought back the thirty pieces of silver to the chief priests and elders,
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saying, "I have sinned in that I betrayed innocent blood." But they said, "What is that to us? You see to it."
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He threw down the pieces of silver in the sanctuary, and departed. He went away and hanged himself.
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The chief priests took the pieces of silver, and said, "It's not lawful to put them into the treasury, since it is the price of blood."
