'Darkness' in the Bible

And I saw that there is an advantage to wisdom above folly, like the advantage of the light above the darkness.

The wise! -- his eyes are in his head, and the fool in darkness is walking, and I also knew that one event happeneth with them all;

Also all his days in darkness he consumeth, and sadness, and wrath, and sickness abound.

For in vanity he came in, and in darkness he goeth, and in darkness his name is covered,

But, if man liveth many years, In all of them let him rejoice, And remember the days of darkness, For they are many! all that is coming is vanity.