The earth was without form and void, and darkness was over the face of the deep. And the Spirit of God was hovering over the face of the waters. - Genesis 1:2
The dark was separated from the light and made into night during creation week.
Spiritually, light is the purest expression of higher meaning. Each component of the universe is a union of heaven and earth, each with a spiritual and material dimension. Dimensions are symbolized by a series of layers in vertical space, with top layers light, supple, simple, bright, and clear and bottom layers heavy, solid, complex, dark, and obscure. The top levels are more implicit and has less corporeal real presence.
Things that are too high are too simple to understand, while things that are too low are too complex. True knowledge is complex enough to be tangible while simple enough to be meaningful.
To the ancients, they played a role in the process of knowledge. Light is linked with spiritual reality, while dark is linked with corporeal reality. Corporeal reality asks a question with the power to host spiritual meaning when answered, so dark matters are considered a cause of revelation and manifestation. When ideas are too abstract to understand, we require detailed examples to appreciate its ramifications.
(The Language of Creation: Cosmic Symbolism in Genesis - A Commentary by Matthieu Pageau, 2018. Pages 35-40)
Abrahamic covenant
In the deep sleep during which God revealed the future of the nation of Israel to Abram, a dreadful and great darkness fell upon him. When the sun had gone down and it was dark, a smoking fire pot and a flaming torch passed between his offering.