When God announces to Abraham His intention to destroy Sodom and Gomorrah and the other cities of the plain, He says, “The outrage of Sodom and Gomorrah is so great and their sin so grave!”
What was the sin of these cities that brought about their destruction? Perhaps you think that this is obvious — surely their sin was sodomy. But it’s not so simple. While the word “sodomy” clearly comes from the Torah’s account of the mob demanding that Lot turn over the guests he had taken into his home so “that we may be intimate with them,” none of the rabbinic commentaries see this as Sodom’s great sin. The rabbis ascribe to Sodom a very different, and probably much more common, sin.
This appears in Pirkei Avot:
There are four temperaments among men: the one who says, “what is mine is mine, and what is yours is yours” — that’s an [average] temperament…. [A second type is one who says] “what is mine is yours, and what is yours is mine” — [that’s an] ignoramus. [A third type is one who says] “what is mine is yours, and what is yours is yours” — [that’s a] saint. [A final type is one who says] “what is yours is mine, and what is mine is mine” — [that’s a] wicked person.
You may have noticed that I left something out of the Mishnah. In the complete text, after “what is mine is mine, and what is yours is yours,” we find, “And there are some who say that is the temperament of Sodom.”
According to the rabbis, the sin of Sodom was that despite the city’s great wealth, none of its inhabitants, both as a matter of character and as a matter of law, would give even a penny to anyone else, no matter how needy that person might be.
According to the midrash Pirkei d’Rabbi Eliezer, the selfishness of Sodom was so great that the inhabitants actually cut the top branches off all the fruit-bearing trees so that not even a passing bird might benefit from anything that belonged to them. The midrash adds that they passed laws to institutionalize their selfishness: “Rabbi Judah said: It was proclaimed in Sodom, ‘He who sustains a stranger or a poor and needy person with a morsel of bread is to be burned alive.’”
The Sodomites’ demand that Lot’s guests be turned over to them makes perfect sense in this context. In Sodom, strangers were not to be welcomed, but turned away. And if they didn’t get the message, they would be forced to leave or even killed.
The Torah contrasts Sodom’s practice with that of Abraham. The beginning of the parasha portrays Abraham as the paradigm of hachnasat orchim (welcoming guests) and he is praised and honored for his unselfish hospitality. Sodom is destroyed because of its selfishness and inhospitality.
What’s mine is mine and what’s yours is yours — this is the temperament of Sodom. And so we are taught that tzedakah (giving to the poor) is not merely a good deed, but a mitzvah, an obligation. In fact, the Talmud teaches that even someone who receives his meals at a soup kitchen is obligated to give some of what he has to another poor person. After all, we know what selfishness brought upon the inhabitants of Sodom.