20:13 Thou shalt not covet…
In general, people understand that it is prohibited to desire other people’s possessions. People also feel a little bit ashamed of themselves that they are not satisfied with what they have, and have to instead imagine owning things that belong to others.
One may think that this prohibition is a prohibition between man and himself: The person who has the coveted item was just the catalyst for the sin to happen. One may even think that this is a sin between man and G-d because the man was not satisfied with the lot which Hashem granted him, but again his fellow man and his item are out of the picture.
There is a story told about the Kotzker Rebbe who heard that there were three pairs of tefillin written by a great tzaddik, who was a talmid of the Magid of Mezrech. He immediately sent a messenger to those in charge of those precious tefillin to find out if they were for sale. He was told they were, but for an exorbitant price. The Rebbe decided that it was well worth his while and “broke his bank”, putting together all the money he could find in order to purchase these tefillin. The messenger went to buy the tefillin with these funds, and when he came back to the Kotzker Rebbe, the messenger said “I would like to apologize. Everyone knows about these holy tefillin and I too wished that they were mine, and I therefore decided to ‘sneak a peek’ and wear them once in my life”. After the Kotzker Rebbe heard this, he said “You can keep the tefillin. I don’t want them at all, because tefillin which were coveted have become tainted to the point that they are useless for me.”
The halacha is that if someone would like to use another person’s tefillin, we assume the owner would be happy if his possessions were used for a mitzvah. Therefore, one may argue that it was permissible for the messenger to wear the tefillin. That would mean that the only sin that was committed was “coveting” the tefillin. Yet, this was enough to make the Kotzker Rebbe not want to wear the tefillin.
In summary, an item that was coveted may lose its holiness and become “soiled”, preventing its use for a mitzvah. If this is true about an item that is holy, then all the more so for a mundane item. Flaunting one’s possessions exposes oneself to an evil eye, as well as to the potential of negatively influences on one’s possessions. Prudence says that it is worthwhile not to stand out and cause others to gawk.
Unfortunately, many times people with these desireable possessions say “It is his obligation keep his eyes off my possessions!” This is not true for two reasons: Firstly, there is an aspect of arvus, obligating the property owner to be responsible for his fellow Jews. Secondly, there is also an aspect of not placing a stumbling block before a fellow Jew. But if these two ideals are not sufficient to motivate one to be modest with one’s possessions, then the realization that someone can actually damage another person’s property through the sin of coveting should help.
Finally, we can learn to be modest and discrete with our possessions from the Tablets containing the Ten Commandments: The Chortkover Rebbe told Rav Meir Shapiro, when it was relevant to making a chanukas habayis, that it should be done modestly, for the first set of tablets, which were given in an opulent manner, were broken; and the second set of tablets, which were given quietly, continue to exist.