Ecclesiastes 2:12-17

Qoheleth turns to the study of human nature in its wisdom and its folly. Though all is vanity yet wisdom is better than folly; it is better to face the outlook, dreary though it be, with intelligence, than to be stupid and dense. The wise man can at least see where he is going; the fool is in a fog, and blind; the eyes of his understanding are darkened. Yet there is no final advantage to the wise, the same death overtakes both wise and foolish, so that unusual wisdom is really a useless endowment. Wise man and fool are alike buried in oblivion (cf. Ecclesiastes 1:11). So I hated life, yet he continued in it. A pessimist who is able to vent his feelings in literary expression does not commit suicide (Barton).