Musar su Salmi 34:11

And there is stealing that is not considered stealing by the laws of people, but is considered stealing by the laws of heaven, such as one who decides in one's mind to enter in judgment with one's friend in order to collect money from the friend without doing violence, just because one's eyes deceived him, and one brings monetary damage to the friend, even without a fight or misuse, just by the simple emotion, having clean hands, and even if from the decision the friend would be forced to pay all, the spirit of the Place does not abide with him, and does this as a tax owed by the friend, one transgresses "love your neighbor as yourself" which is a general rule in the Torah, and it is in instances like this that they said "a person is known by their pocket" (Eruvin 65b). And according to the basic material, stealing is forbidden and the teshuvah is difficult, behold it says "one who steals even a cent from one's friend is likened to one who stole the soul from the friend, and the soul from the friend's sons and daughters" (Bava Kamma 119a) and while the stolen money is in one's hands there is no possible atonement, and it is very difficult to return food that was stolen (Chulin 99a). And behold a person who fears Hashem will be cautious and will guard oneself very much from anything that is forbidden in any aspect it can exist, and will deal all one's business faithfully, and even when a good opportunity appears, and those who sell are being stricken with harsh punishments, one will never extend one's hands towards stealing God forbid, because it is better for a person to die of starvation than to become an evildoer even for an hour in the Place's eyes, and "those who seek Hashem do not lack what is good" (Ps. 34:11) because God does not withhold good to those who walk in simple ways.

We may understand the word שלי as referring to what is material, whereas the word שלך in the Mishnah in question refers to the mind, the abstract. When a person proclaims: שלי שלי ושלך שלי, it is as if he said: The body and the mind both belong to the secular, to earth-bound values. This is typical of the wicked person who wants to make life a totally physical experience and to drag down the spiritual part of man to the level of the merely physical. When a person declares: שלך שלך וגם שלי שלך, he is described as pious because he expresses his striving to elevate what is physical to the level of the spiritual. The person who says: שלי שלך ושלך שלי is similar to the person of whom Solomon said in Kohelet 2,24: "Is it not good for a man to eat and drink and enjoy?" Solomon refers to the person who wishes to partake of "both tables," i.e. life in the here and now as well as life in the Hereafter. When he refers to the enjoyment, he refers to the joy of studying Torah. Whereas some of our sages consider this attitude as average, i.e. tolerable, others consider it as the attitude espoused by the people of Sodom. The Rabbis who see in this attitude an average attitude believe that a philosophy of זה נהנה וזה לא חסר, "The fact that one person derives pleasure but not at the expense of his fellow," is something morally tolerable. It is similar to someone who lights his candle from another candle. He secures light for himself without diminishing the existing light for others. These rabbis compare such conduct to the verse in Psalms 34,11: ודורשי ה' לא יחסרו כל טוב, "Those who turn to the Lord are not failing to do something wholly good." The motto of: "What is mine is yours and what is yours is mine," is equivalent to turning the laws of nature upside down. When a person turns the weekday into the Holiday by denying himself all physical pleasure on weekdays, whereas he uses the Holidays for unbounded physical enjoyment, he reverses the order G–d has established for this world and is clearly ignorant of G–d's plans. The Torah has spelled out that only certain activities are allowed on the Holidays in order to ensure our minimal physical comfort on such days. This is the meaning of Exodus 12,16: אך אשר יאכל לכל נפש הוא לבדו יעשה לכם, "Only what every person has to eat, that alone may be prepared for you." When we examine what the author of Emek Berachah writes in connection with the above Mishnah we find that the desire to enjoy both the physical parts of this world as well as the spiritual ones is not enough for a person who wants to qualify as pious. People such as the prophets Elijah and Chanoch learned how to cope while availing themselves of less and less of the comforts available for the body in this world. In order to establish the closest possible ties with G–d the physical part of this world cannot be enjoyed in its own right. The enjoyment of the Holiday should comprise the life-force of the body, נפש הגופני, as well as the life-force of the soul, נפש הרוחני, through the study of Torah and engaging in prayer.