Ecclesiastes Rabbah 6:11

¹“As there are many matters that increase vanity, what remains for the person?” (Ecclesiastes 6:11). “As there are many matters that increase vanity,” such as breeders of monkeys, cats, porcupines, chimpanzees, and seals; what benefit do they get from them? [They will eventually give their owner] either a bite or a sting. What benefit? It is either an injury or a wound. Likewise, one who removes stones from his field and places them in the public domain, what benefit does he have? It [will be] either an obstacle or [cause] a scratch, and some say: A crippling injury. There was an incident involving a certain pious man who was removing stones from his field and placing them in the public domain. There was a certain other pious man who pursued him and said to him: ‘Why are you removing stones from a place that is not yours, and placing them in a place that is yours?’ He laughed at him. Several days later, that pious man was in need and sold his field. He was walking in the public domain and stumbled. He said: ‘It was not for naught that this pious man said to me that I am placing it in my own property.’ “What remains for the person?”