(י) אַרְבַּע מִדּוֹת בָּאָדָם. הָאוֹמֵר שֶׁלִּי שֶׁלִּי וְשֶׁלְּךָ שֶׁלָּךְ, זוֹ מִדָּה בֵינוֹנִית. וְיֵשׁ אוֹמְרִים, זוֹ מִדַּת סְדוֹם. שֶׁלִּי שֶׁלְּךָ וְשֶׁלְּךָ שֶׁלִּי, עַם הָאָרֶץ. שֶׁלִּי שֶׁלְּךָ וְשֶׁלְּךָ שֶׁלָּךְ, חָסִיד. שֶׁלִּי שֶׁלִּי וְשֶׁלְּךָ שֶׁלִּי, רָשָׁע:
(10) There are four types of character in human beings: One that says: “mine is mine, and yours is yours”: this is a commonplace type; but some say this is a sodom-type of character. [One that says:] “mine is yours and yours is mine”: is an unlearned person (Am Haaretz); [One that says:] “mine is yours is yours is yours” is a pious person. [One that says:] “mine is mine, and yours is mine” is a wicked person.
(א)מדת סדום. (עם שבלי ספק היה דבר מועיל מאד בתקון קבוץ המדיני אם היה כיס אחד לכולם. כי אז בטלה קנאה ושנאה מבני אדם. ולכן היו נמצאים בדורות קדמונים כתות פרושים בישראל שכל נכסיהם היו בשותפות אין לאחד זכות בשום דבר מהקנינים לעצמו יותר מחבריו. אלא כולם נזונים מן האמצע. כמ"ש מהם בס' יוסיפון).
It would certainly be very beneficial for society at large if there would be one collective "pot" for everyone, for that would eradicate jealousy and hatred.
Indeed, there were Jewish groups in antiquity who relinquished all personal possesions to a collective, shared pool, without retaining any ownership.
They would then sustain themselves from the shared pool, as described in Josephus.
(ג)שֶׁלִּי שֶׁלְּךָ וְשֶׁלְּךָ שֶׁלִּי עַם הָאָרֶץ. שֶׁנֶּהֱנֶה וּמְהַנֶּה בְּשָׁוֶה, וְזֶהוּ יִשּׁוּבָהּ שֶׁל הָאָרֶץ, אֲבָל אֵינוֹ יוֹדֵעַ קְרָא דִּכְתִיב (משלי טו) וְשׂוֹנֵא מַתָּנוֹת יִחְיֶה. וְזֶהוּ לְשׁוֹן עַם הָאָרֶץ הָאָמוּר בְּכָל מָקוֹם, שֶׁרוֹצֶה בְּתִקּוּנָהּ שֶׁל הָאָרֶץ אֲבָל אֵין בּוֹ חָכְמָה לְהַבְדִּיל בַּתִּקּוּנִין הָרְאוּיִין:
(3)"what is mine is yours, and what is yours is mine" -- [that's an] am ha'arets (uneducated person, literally the people of the land): who benefits and gives benefit equally, and this is [for] the [advancement of] the inhabitation of the land. But he doesn't know the verse (Proverbs 15:27) which writes, "and the one hates gifts will live." And this is the [meaning] of the expression, am ha'arets, in every place - that he wants the refinement of the land but he does not have the wisdom to distinguish [what are] proper refinements.
Be'er Avot Ad Loc
An alternative explanation for the words "' What is mine is yours, and what is yours is mine" is an Am Ha'aretz": Such a person wishes to repair the worldly order, claiming that all should have an equal share in life's essentials, and no person should have personal property.
Such a person claims that this will bring mutual benefit for all, as everyone will do what they are most skilled at, and the livelihood of all will come from a communal “pot”. In this manner, any concept of “mine” or “yours” will be abolished; rather, “what is mine is yours, and what is yours is mine.”
Although these people claim that with the socialist model, man will eventually bear a natural drive to work, such a nature is only born if the human is coerced to work- and without any perspective of real reward for their production.
To what is this analogous? Two teachers; one seeks to attract his students with kind words and presents, while the other seeks to attract his students with coercion, hitting and abusing them. Any sensible person understands that the former’s method is correct, while the latter’s is counterproductive to its stated goal.
So the matter is with society: If a person can amass wealth by virtue of his own innovations and efforts commensurate to the extent of his labor, talents, and intellect, certainly this will overpower his natural tendency of laziness. Such results would never be produced by coercion and policing, not to mention by famine and deprivation.
Thus, the stages of our Mishnah label such a person an “Am Haaretz,” for he is steeped in his peasantry, lacking the intellectual intuition to understand the ways of the world.
Igrot Kodesh Volume 23 Page 263
A fundamental principle of communal living is to equate all people - which, incidentally, opposes human nature. Just as no two faces are alike, no two people are inherently alike either. An individual finds fulfillment and satisfaction when they are able to realize all their latent potential to the fullest degree. A person naturally wants to express their individual qualities and talents which set them apart from their peers, and not so much with the qualities that they share with everyone else - for our individual qualities are our very essence.
Granted, a person does not wish to live alone either, nor is it good for them to do so, and they will seek a communal environment in and through which they can realize their full potential.
The purpose of communal living is not to quash all competition. In fact, one of the principal elements that spur creativity, innovation, and advancements is challenge and competition.
אמר רב יהודה אמר שמואל כל כסף וזהב שבעולם יוסף לקטו והביאו למצרים שנאמר וילקט יוסף את כל הכסף הנמצא אין לי אלא שבארץ מצרים ושבארץ כנען בשאר ארצות מנין תלמוד לומר וכל הארץ באו מצרימה
Rav Yehuda said that Shmuel said: Joseph collected all the silver and gold in the world and brought it to Egypt, as it is stated: “And Joseph collected all the money found in the land of Egypt and in the land of Canaan” (Genesis 47:14). I have derived only that he collected the money that was in the land of Egypt and that was in the Land of Canaan. From where do I derive that he also collected all the money that was in other lands? The verse states “And all the land came to Egypt to buy food from Joseph, because the famine was sore in all the earth” (Genesis 41:57).