That is that He commanded us to justify the leveler, the scales, the weights and the measures; and to maximize their exactness. And that is His, may He be exalted, saying, "Just scales" (Leviticus 19:36). And the language of the Sifra (Sifra, Kedoshim 8:7) is, "'Just scales' - justify the scales well. 'Just weights' - justify the weights well. 'A just ephah' - justify the ephah well. 'And a just hin' - justify the hin well." And it is already known that the ephah is the dry measure and the hin is the wet measure. And all of these matters are one, [even] if the type of measure varies according to the thing that is weighed or measured - regardless, it is a measurement that is evaluated. And all of these - meaning, the leveler, the scales and the ephah - are called measures; and the command, that we have been commanded to maximize the exactitude of the accepted measurement for each and every type, is called the commandment of measures. And the language of the [Sifra] (Sifra, Kedoshim 8:10) is, "On this condition, I brought you out of the Land of Egypt - that you take upon yourselves the commandment of measures. For all who acknowledge the commandment of measures, acknowledge the exodus from Egypt; and all who deny [it], deny the exodus from Egypt." And the regulations of this commandment have already been explained in the fifth [chapter] of [Bava] Batra. (See Parashat Kedoshim; Mishneh Torah, Robbery and Lost Property 8).

You shall have an honest balance, honest weights, an honest ephah, and an honest hin. I יהוה am your God who freed you from the land of Egypt.

It is a positive commandment to correct the scales, weights and measures carefully and to be exact in their measure when making them, as Leviticus 19:36 states: "You shall have correct scales...."Similarly, with regard to the measurement of land, one must be exact according to the principles of geometry. Even a fingerbreadth of land is considered to be a great loss, as if it were filled with saffron.

Weights should not be made of iron, lead or other metals of that nature, for they rust and become reduced in weight. One should make them from marble, glass, diamond and the like.

One may not bury weights in salt so that their weight will be reduced, nor may one heat while measuring a liquid.This applies even if the measure is very small, for the Torah was concerned with even the slightest deviation from an honest measure, as implied by the mention of a mesurah in Leviticus 19:35. A mesurah is a very tiny measure, merely a thirty-third of a log.

Sellers of scrap iron and the like should construct the scale they use in the following manner. The balance that the person who is weighing holds in his hands should hang freely in the air for at least three handbreadths, and should be three handbreadths above the ground. The length of the center pole and the length of the cables should be twelve handbreadths.

A scale used by wool merchants and glass merchants should be constructed in the following manner. The balance should hang freely in the air for at least two handbreadths and should be two handbreadths above the ground. The length of the center pole and the length of the cables should be nine handbreadths.

A scale used by an ordinary storekeeper and a house-owner should be constructed in the following manner. The balance should hang freely in the air for at least one handbreadth, and should be one handbreadth above the ground. The length of the center pole and the length of the cables should be six handbreadths.

What is the source that teaches us that one must tip the balance in favor of the purchaser when his purchase is being weighed for him? Deuteronomy 25:15 states: "You shall have a perfect and just weight." The Torah's statements can be interpreted to mean: "Justify your balance from what you have and give it to him."

A wholesale merchant must clean his measures once every 30 days. A house-owner must do this every twelve months, and a storekeeper twice a week. Once a week, he must wash his weights, and he should clean the balance after every time that he weighs, so that it will not rust.

The court is obligated to appoint police in every city and town to inspect the stores periodically, correct the scales and measures, and set the prices. They are permitted to beat any person who possesses an unjust measure or weight or an improper balance according to his capacity, and to fine him as the court sees fit to enforce the matter.Whenever a person raises prices and sells at a higher price, he may be beaten and compelled to sell at the ordinary market price.

§ Rabbi Levi says: The punishment for using false measures is more severe than the punishment for transgressing the prohibition of forbidden sexual relations. As in that case, forbidden relations, it is stated with regard to them a shortened term for the word “these”: “El,” in the verse: “For all these [el ] abominations” (Leviticus 18:27). And in this case, false measures, it is stated an expanded term for the word “these”: “Elleh,” in the verse: “For all that do these [elleh] things, even all that do unrighteously, are an abomination unto the Lord your God” (Deuteronomy 25:16). And from where may it be inferred that this expression “el” indicates that the prohibition is severe, based on which it is understood that the form this word takes indicates a level of severity? As it is written: “And the mighty [eilei] of the land he took away” (Ezekiel 17:13).

For everyone who does those things, everyone who deals dishonestly, is abhorrent to your God יהוה.

for all those abhorrent things were done by the people who were in the land before you, and the land became defiled.

The Gemara asks: But with regard to forbidden relations isn’t it also written: “For whosoever shall do any of these [elleh] abominations” (Leviticus 18:29)? If so, why is the punishment for using false measures considered harsher? The Gemara answers: That expression of “elleh” (Leviticus 18:29) in the context of forbidden relations does not serve to emphasize its severity. Rather, it serves to exclude one who uses deception in measures from the penalty of excision from the World-to-Come [karet].

All who do any of those abhorrent things—such persons shall be cut off from their people.

The Gemara asks: But if the punishment is in fact less severe, what is the advantage, i.e., the greater severity, in the case of false measures? The Gemara answers that there, in the case of one who engages in forbidden relations, he has the possibility of repentance. But here, in the case of one who uses false measures, there is no possibility of repentance because he has no way of knowing whom he cheated, and is therefore unable to return the stolen money.

The punishment for the person who uses false measures is greater than the punishment for licentious sexual behavior, for this is a sin between a person and his colleague, and this is a sin between a person and God.Whoever denies the mitzvah of just measures is considered as if he denied the exodus from Egypt, which is the first of God's commandments. Conversely, one who accepts the mitzvah of just measures is considered as if he acknowledges the exodus from Egypt, which brought about all of God's commandments.