Darkness means that there is no light at all. This happens each night when the sun sets until the moon rises, and a darkness of the soul can refer to someone who is evil and who has no goodness or redeeming qualities. A fear of darkness is common in children and many adults, because it is not possible to see your surroundings or determine if there is anything to be scared of.
When you go through deep waters, I will be with you. Isaiah 43:2
I would rather walk with a friend in the dark, than alone in the light.
The guilty one is not he who commits the sin, but the one who causes the darkness
In darkness one may be ashamed of what one does, without the shame of disgrace