"The fool folds his hands and ruins himself. Better one handful with tranquility than two handfuls with toil and chasing after the wind." NIV translation
Now, he contrasts the lazy with those that are chasing after the riches of the world. Solomon's conclusion is that it is better to work and have peace with what you have than to be lazy or to always be chasing for more. This is what the apostle Paul was talking about when he described his contentment (see Philippians 4).
"Again I saw something meaningless under the sun: There was a man all alone; he had neither son nor brother. There was no end to his toil, yet his eyes were not content with his wealth. 'For whom am I toiling,' he asked, 'and why am I depriving myself of enjoyment?' This too is meaningless - a miserable business!" NIV translation
Now, he shows us that it is meaningless to acquire wealth and have nobody to share it with. As it was in the garden, man was not created to be alone like an island in the ocean.
"Two are better than one, because they have a good return for their work: If one falls down, his friend can help him up. But pity the man who falls and has no one to help him up! Also, if two lie down together, they will keep warm. But how can one keep warm alone? Though one may be overpowered, two can defend themselves. A cord of three strands is not quickly broken." NIV translation
Solomon gives us examples of how two are better than one but then ends the passage speaking of a three stranded cord. This makes us wonder what he is talking about and we find the answer in Genesis 2. There we see that a woman was created to be with a man and they were to work together. The third cord is God as they were designed to work together with God to fulfill His plan for their lives. A man and woman walking and working together for the glory of God is the only way that a life has lasting meaning.