'Dark' in the Bible

The sun will become dark and the moon will be turned to blood, before that great day of the Lord comes in glory:

And now, see, the hand of the Lord is on you, and you will be blind and not able to see the sun for a time. And straight away a dark mist came down on him; and he went about looking for a guide.

To make their eyes open, turning them from the dark to the light, and from the power of Satan to God, so that they may have forgiveness of sins and a heritage among those who are made holy by faith in me.