Arcana Coelestia #21
21. Verses 4-5 And God saw that the light was good; and God made a distinction between the light and the darkness. And God called the light Day, and the darkness He called Night.
The light is called good, because it comes from the Lord, who is good itself. 'The darkness' is those things which were there prior to the person's new conception and birth. They were seen as light, because evil was seen as good, and falsity as truth. But in reality they are darkness and things proper to that person which are lingering on. All things that are the Lord's, being things of light, are compared to the day, and all that are man's own, being those of thick darkness, are compared to the night, as is done many times in the Word.
Matthew 22:11-13
11
But when the king came in to see the guests, he saw there a man who didn't have on wedding clothing,
12
and he said to him, 'Friend, how did you come in here not wearing wedding clothing?' He was speechless.
13
Then the king said to the servants, 'Bind him hand and foot, take him away, and throw him into the outer darkness; there is where the weeping and grinding of teeth will be.'