'Darkness' in the Bible

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

The wise man has eyes in his head,but the fool walks in darkness.Yet I also knew that one fate comes to them both.

What is more, he eats in darkness all his days, with much sorrow, sickness, and anger.

For he comes in futility and he goes in darkness, and his name is shrouded in darkness.

Indeed, if a man lives many years,let him rejoice in them all,and let him remember the days of darkness, since they will be many.All that comes is futile.