'Gain' in the Bible

What does a man gain for all his effortsthat he labors at under the sun?

So I thought to myself, "The fate of the fool will happen even to me! Then what did I gain by becoming so excessively wise?" So I lamented to myself, "The benefits of wisdom are ultimately meaningless!"

For what does a person gain from everything that he accomplishes and from his inner life struggles that he undergoes while working on earth?

What does the worker gain from his struggles?

He who loves money will not be satisfied with money, nor he who loves abundance with its gain. This too is vanity (emptiness).

When someone's prosperity increases, those who consume it also increase; so what does its owner gain, except that he gets to see it with his eyes?

This too is a sickening tragedy: exactly as he comes, so he will go. What does the one gain who struggles for the wind?

So what advantage does a wise man have over a fool? And what advantage does a pauper gain by knowing how to survive?

Unjust gain makes the wise foolish, and a bribe corrupts the heart.

When I tried to gain wisdom and to observe the activity on earth -- even though it prevents anyone from sleeping day or night --

Blessed are you, O land, when your king is a son of nobility and your princes feast at the proper time-- to gain strength and not to get drunk.