'Knows' in the Bible

Who knows if he will be a wise man or a fool? Yet he will be master over all the fruit of my labor for which I worked so wisely on earth! This also is futile!

Who really knows if the human spirit ascends upward, and the animal's spirit descends into the earth?

A poor but wise youth is better than an old and foolish king who no longer knows how to receive advice.

For no one knows what is best for a person during his life -- during the few days of his fleeting life -- for they pass away like a shadow. Nor can anyone tell him what the future will hold for him on earth.

Who is a wise person? Who knows the solution to a problem? A person's wisdom brightens his appearance, and softens his harsh countenance.

Whoever obeys his command will not experience harm, and a wise person knows the proper time and procedure.

Surely no one knows the future, and no one can tell another person what will happen.

So I reflected on all this, attempting to clear it all up. I concluded that the righteous and the wise, as well as their works, are in the hand of God; whether a person will be loved or hated -- no one knows what lies ahead.

Surely, no one knows his appointed time! Like fish that are caught in a deadly net, and like birds that are caught in a snare -- just like them, all people are ensnared at an unfortunate time that falls upon them suddenly.

yet a fool keeps on babbling. No one knows what will happen; who can tell him what will happen in the future?