Darkness is used in Scripture as a metaphor for evil to represent all that is sinful and satanic.
In contrast, light is a biblical metaphor for good to represent truth and all that is of God.
The apostle Paul instructed, “Therefore do not be partakers with them. For you were formerly darkness, but now you are light in the Lord. Walk as children of light—for the fruit of the Spirit is in all goodness and righteousness and truth … And do not have fellowship with the unfruitful works of darkness; instead, expose them” (Eph. 5:7-9, 11).
It’s a tricky balance for Christians to be in the world without conforming to it.
Jesus prayed, “I do not pray that You should take them out of the world, but that You should keep them from the evil one” (John 17:15).