'Labor' 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!

So I began to despair about all the fruit of my labor for which I worked so hard on earth.

For a man may do his work with wisdom, knowledge, and skill; however, he must hand over the fruit of his labor as an inheritance to someone else who did not work for it. This also is futile, and an awful injustice!

What does a man acquire from all his labor and from the anxiety that accompanies his toil on earth?

Two people are better than one, because they can reap more benefit from their labor.

God gives a man riches, property, and wealth so that he lacks nothing that his heart desires, yet God does not enable him to enjoy the fruit of his labor -- instead, someone else enjoys it! This is fruitless and a grave misfortune.

All of man's labor is for nothing more than to fill his stomach -- yet his appetite is never satisfied!