Bava Basra, Chapter Five, Mishnah Ten. The final two Mishnayos of the chapter move to a new topic: although we are still dealing with monetary transactions, these two Mishnayos emphasize the necessity for commercial transactions to be precise and just - precision in weights and measures.
The foundation of this concept in the verse:
Several verses emphasize this matter due to its great importance, and the most essential of them for our purposes is: "Even sheleimah vatzedek yihyeh lach, eifah sheleimah vatzedek yihyeh lach" - a perfect and just weight you shall have, a perfect and just measure you shall have. An "even" is literally a stone, referring to the weight placed on a balance scale to weigh items, and an "eifah" is a vessel for measuring volume. In both of these, two virtues are required:
"Sheleimah" - perfect, meaning the measure must be its exact weight, without any shortfall.
"Vatzedek" - and just. This appears to be an extra word, as we already said the measure is exact. However, the justice here, related to the word tzedakah (charity), implies tipping the scale - both literally and metaphorically - in favor of the buyer, and going beyond the letter of the law. This concept will be explained in the next Mishnah, while our Mishnah deals with the "sheleimah" aspect, the precision of the measures and weights.
It is worth noting the conclusion of the verse: "So that your days may be lengthened on the land that Hashem your God is giving you." Many people look for segulos (spiritual remedies), and here is an explicit segulah from the Holy One, Blessed is He, Himself - long life and dwelling securely in the Land of Israel, as a reward for precision in weights and measures, which represent honesty and fairness in commercial business.
Three types of sellers:
Hasiton - the wholesaler, who conducts transactions with high frequency.
Baal habayit - a private individual who grows produce and sells it in the market from time to time.
Hachenvani - the storekeeper, who is constantly engaged in measuring and weighing.
Cleaning the measuring vessels:
The first part of the Mishnah deals with measuring vessels, and the question is how often a person is obligated to clean them. The concern is the accumulation of residue over time: the measuring vessels were not made of glass but of earthenware, and the liquid being sold leaves dirt that sticks to the sides. If a cubic centimeter of residue accumulates in the vessel, the seller thinks he is measuring a full liter, but in practice, he is only giving 999 cc with each measurement - and ends up cheating his customer. Therefore, there is an obligation to wipe away the waste that sticks to the sides of the vessel.
We learned: "Hasiton mekane'ach middosav achas lishloshim yom, u'va'al habayit achas lishneim asar chodesh" - the wholesaler wipes his measures once every thirty days, and the baal habayit once every twelve months. The wholesaler, whose entire business is measuring, wipes his measuring vessels once every thirty days; whereas the baal habayit, who measures infrequently, and therefore has minimal dirt accumulation, wipes them once every twelve months. This is the opinion of the Tanna Kamma.
Rabban Shimon ben Gamliel says: "Chiluf hadevarim" - the reverse is true. The wholesaler once every twelve months, and the baal habayit once every thirty days. His reasoning: vessels that are used continuously, as is the way of the wholesaler, do not dry out, and consequently there is less opportunity for residue to accumulate in them. In contrast, the baal habayit, who uses his vessels infrequently, at the time of receiving the harvest and the like, leaves time for the remnants to dry and stick, and therefore he must wipe them with greater frequency.
As for the storekeeper, who engages in measuring even more frequently than the wholesaler, we learned: "Mekane'ach middosav pa'amayim bashabbos" - he wipes his measures twice a week. Here, Rabban Shimon ben Gamliel does not argue, and on the surface, this is puzzling. According to the Tanna Kamma, everything depends on frequency: the baal habayit measures minimally, so twelve months; the wholesaler measures frequently, so thirty days; and the storekeeper measures all the time, and therefore twice a week. But Rabban Shimon ben Gamliel holds that the more the usage, the smaller the concern for accumulation, and the storekeeper uses his vessels more than anyone - why then does he not argue?
The answer is found in what we learned a few Mishnahs earlier: the shopkeeper, when pouring from a measuring vessel, does not wait for the last three drops to drip out, because he is rushing to the next customer. As a result, a little liquid always remains at the bottom of his vessel, even if he measures ten times a day, and the vessel is always wet. Therefore, there is a greater concern that a hard residue will form, and even Rabban Shimon ben Gamliel agrees that he must wipe it out twice a week.
From Measures to Weights:
From here, the Mishnah transitions, as if in the middle of the topic, from liquid volume measures to the weights used for weighing, such as when selling fish or meat by the litra. During the time of the Mishnah, they used a pan balance: two pans hanging by a string or a peg from above, similar to the familiar symbol of justice and the zodiac signs. If someone wants to buy a litra of fish - the litra weight is placed on one of the pans, and the fish on the other, until the pans balance. The heavier side goes down, and when the weight is equal, the two pans align.
Here too, the question is how often a person is required to clean his weights. When selling wet items, liquids stick to the weight, dry out, and accumulate, making the weight heavy and inaccurate. The Mishnah says: "Umemacheh mishkelosav pa'am achas bashabbos" - he wipes his weights once a week. This refers to a shopkeeper, who frequently deals with small weights, and not to a wholesaler or a homeowner, who do not usually use this type of scale.
At first glance, one might wonder: if residues stuck to the weights, they are now too heavy, which is actually to the buyer's advantage. A one-litra weight with dried fish oil stuck to it now weighs 1.01 litras, and the buyer will receive extra fish. What then is the problem?
There are two reasons for this:
Sometimes the shopkeeper is the one buying from a supplier. When he weighs the merchandise with his own weights, and they are heavier than they should be, he ends up receiving 1.01 litras of fish while paying for only one litra - which is cheating the supplier.
Even toward the buyer, there is a concern. The shopkeeper cannot keep every possible weight on hand, so he has a one-litra weight and a three-litra weight. A buyer comes to purchase two litras of fish - the shopkeeper places the three-litra weight on one pan, and the fish together with the one-litra weight on the other pan, resulting in two litras of fish. But if that weight placed next to the fish weighs 1.01 litras, the pans balance earlier, and the buyer receives less fish.
Therefore, the weights must be cleaned at least once a week, so that they will be accurate.
The Mishnah adds: "Umekane'ach moznayim al kol mishkal umishkal" - he must wipe the scale pans themselves between every weighing. The pan of the scale is like a plate or a rimmed bowl, which holds any drippings; and when weighing wet items, like fish, liquids remain on it, and the next buyer will not receive the full amount he purchased. As the Mishnah explicitly states, this only applies to items that leave a residue; for dry items, which leave nothing on the scale, there is no need to wipe it every time.
In summary: Although this seems like an abundance of details, the fundamental point is one - a person has an obligation to maintain accurate weights and measures. The Rema even writes that every city should appoint its own enforcement agency, which periodically checks the merchants' weights and measures and strictly enforces the law against anyone whose weights are inaccurate, so that honesty will prevail in the markets and people will not be deceived. We learn from here that this is a highly important and exalted value in the Torah, and a person must be extremely careful regarding it.