'Darkness' in the Bible

The sun will be turned into darkness, and the moon into blood, before the great and glorious day of the Lord comes.

Now, behold, the hand of the Lord is on you, and you will be blind, not seeing the sun for a season!" Immediately a mist and darkness fell on him. He went around seeking someone to lead him by the hand.

to open their eyes, that they may turn from darkness to light and from the power of Satan to God, that they may receive remission of sins and an inheritance among those who are sanctified by faith in me.'