Sefer HaChinuch ספר החינוך

The commandment of having just scales, weights and measures: To have just scales, weights and measures and to be very careful about them, as it is stated (Leviticus 19:36), “You shall have just scales, just weights, a just eiphah, and a just hin.” And the language of Sifra, Kedoshim, Chapter 8:7 [is] “‘Just weights’ — justify the scales precisely” — meaning to say, that the scales be righteous. And the matter is well-known regarding scales that there are important adjustments to make, as it is possible to do many types of falsehood with them. “‘Just weights’ — justify the weights precisely” — also with weights, it is also possible to do many types of falsehood, and similar to that which they, may their memory be blessed, said (Bava Metzia 61b), “I will repay in the future anyone who submersed his weights in salt.” “‘A just eiphah’ — justify the eiphahs precisely; ‘and a just hin’ — justify the hin precisely.” And an eiphah is a dry measure and a hin is a liquid measure. And the Torah warned us about each and every one of these things specifically, due to the severity of the matter — and even though it is all included in the principle of “And a man shall not cheat his compatriot.” And the language of Sifra, Kedoshim, Chapter 8:10 [is] “On condition of this, I took you out from the land of Egypt — that you accept upon yourselves the commandment of measures.” And they, may their memory be blessed, also said (Bava Metzia 61b), “I am He Who distinguished in Egypt between the drop of a firstborn and the drop that is not of a firstborn, and I am [He Who is] destined to exact punishment from one who submerses his weights in salt” in order to cheat the creatures, since they do not notice it.

The root of the commandment of righteousness and the distancing from robbery and deceit among people is well-known to all intelligent people.

From the laws of the commandment is, for example, that which they, may their memory be blessed, said (Bava Batra 89a), that we do not make weights out of tin and lead and from any of the other types of metal, since they bring up rust and become lacking, but we [rather] make them out of stone and glass and what is similar to them; and the things that they said regarding the measurement of land; and that which they taught us about the shape of the leveler, that they call rasero in the vernacular. And they also said (Bava Batra 89b) that he should not cause foam in a liquid measure at the time that he measures, and even if it was the smallest measure. As behold, we have found that the Torah is concerned with measures about the smallest amount. As it is stated (Leviticus 19:35), “You shall not pervert justice with measures of length, weight or capacity (mesurah)”; and mesurah is the smallest measure, as it is one thirty-third of a log. And the sizes that they, may their memory be blessed, gave to the length of the bar of the scales and the length of the strings; and the distinction that they said between scales that are made to weigh one type and the scales for another type; and that which they said that the court is obligated to set up supervisors in each and every place to make rounds to regulate the scales and weights, and they have the authority to fine the money, and [even] the body of anyone with whom lacking scales are found; and the rest of its details [are] in the fifth chapter of [Bava] Batra. (See Tur, Choshen Mishpat 231.)

And [it] is practiced in every place and at all times by males and females. And one who transgresses it violates a positive commandment, besides having violated the negative commandment of cheating, of robbing and of stealing — if there is the value of a small coin in it. And that which is most difficult regarding the matter is that one who lies with measures will not pay attention to all of the customers; and [so] he does not know from whom he robbed, such that he [may] return his theft to him. And this is what they, may their memory be blessed, said (Bava Batra 88b), “Very difficult is the punishment for measures.”