Ecclesiastes suddenly turns into Proverbs with a series of oddly disjointed aphorisms. First, be careful when going to the temple and only make mindful sacrifices and for heaven's sake, don't talk too much.
If you make promises to god, keep them or he'll think you're an idiot. In fact, it's better not to make a vow to god than to make one that you can't fulfill. Then don't complain to the angels that you didn't actually mean it when you promised to keep your room clean if god would make your parents give you a puppy for your birthday. I don't even know where to start.
You can just ignore oppression and injustice, because everyone has a boss except the highest boss.
Everyone has the right to profit from the land, even the king. As this book has already said, there is nothing new under the sun. People are never satisfied with what they have. If crop yields increase, so does family size, so what good is wealth?
Workers sleep well, but rich people's wealth doesn't allow them to. My heart bleeds. As A&E has abundantly demonstrated, hoarding is not good for you. Don't make risky investments.
You can't take it with you, so eat drink and be merry. If you're rich, it's because god ever-so-conveniently made you that way.