'Darkness' in the Bible

Then I saw that wisdom excelleth folly, as far as light excelleth darkness.

The wise man's eyes are in his head; but the fool walketh in darkness: and I myself perceived also that one event happeneth to them all.

All his days also he eateth in darkness, and he hath much sorrow and wrath with his sickness.

For he cometh in with vanity, and departeth in darkness, and his name shall be covered with darkness.

But if a man live many years, and rejoice in them all; yet let him remember the days of darkness; for they shall be many. All that cometh is vanity.