'Darkness' in the Bible

And I saw that wisdom excelleth folly, as light excelleth darkness.

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

All his days also he eateth in darkness, and hath much vexation, and sickness, and irritation.

For it cometh in vanity, and departeth in darkness, and its name is 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.