What does Ecclesiastes 4:8-10 mean?

There was a certain man without a dependent, having neither a son nor a brother, yet there was no end to all his labor. Indeed, his eyes were not satisfied with riches and he never asked, "And for whom am I laboring and depriving myself of pleasure?" This too is vanity and it is a grievous task. Two are better than one, because they have a good reward for their labor. For if they fall, one will lift up his companion. But woe to him who is alone when he falls for he has no one to help him up.