
It's hard to picture any system of ethics which demands more meticulous honesty and integrity than Orthodox Judaism. Even keeping in ones house a false weight to be used as a chamber pot is forbidden.
The Torah teaches "You shall do no unrighteousness in judgment, in length, in weight, or in measure. Just balances, just weights, a just ephah, and a just hin, shall ye have: I am the LORD your God, who brought you out of the land of Egypt." Leviticus 19:35-36
I recently studied a section of the Talmud which discusses the issue of using accurate weights and measures.
Our Rabbis taught: Whence [may it be inferred] that [the measure] must not be levelled where the practice is to heap it up, and [that] it must not be heaped up where the practice is to level it? — For it has been definitely stated, A perfect … measure. And whence [may it be inferred] that we are not to listen to one who Says, 'I will level where the practice is to heap up, and reduce the price' or 'I will heap up where they level, and raise the price'? — For it has been definitely stated, A perfect and just measure thou shalt have.
Our Rabbis taught: Whence [is it to be inferred] that the exact weight must not be given where the practice is to allow overweight, and that overweight must not be allowed where the practice is to give the exact weight? — For it has been definitely stated, A perfect weight. And whence [may it be inferred] that we are not to listen to one who says, 'I will give the exact weight where the practice is to allow overweight, and reduce the price', or 'I will allow overweight where they give the exact weight, and raise the price'? — For it has been definitely stated, A perfect and just weight. Rab Judah of Sura said: Thou shalt not have [anything] in thy house; why? — Because of [thy] diverse measures. Thou shalt not have [anything] in thy bag; why? — Because of [thy] diverse weights. But [if thou keep] a perfect and just weight, thou shalt have [possessions]; [if] a perfect and just measure, thou shalt have [wealth].
Our Rabbis taught: [It is written], You shall do no unrighteousness in judgments in meteyard, in weight. or in measure. In meteyard relates to the measuring of ground; one should not measure out for one person in the hot season and for another in the rainy season. In weight, [means] that one shall not keep his weights in salt. In measure, that one shall not cause [liquids] to froth. And by inference from minor to major, [the following may be deduced]. If the Torah cared [for proper measure in] a mesurah which is one thirty-sixth of a log. how much more [should one be careful to give proper measure in the case] of a hin half a hin, a third of a hin, a quarter of a hin, a log, half a log, a quarter [of a log], a toman, half a toman and an 'ukla!
Rab Judah said in the name of Rab: A person is forbidden to keep in his house a measure [which is either] smaller or larger [than the nominal capacity] even if [it is used as a] urine tub.


