Ecclesiastes 6:11-12

11For there are many other words that increase futility. What then is the advantage for a man?

12For who [limited by human wisdom] knows what is good for man during his lifetime, during the few days of his futile life? He spends them like a shadow [staying busy, but achieving nothing of lasting value]. For who can tell a man what will happen after him [to his work, his treasure, his plans] under the sun [after his life is over]?