After the Torah introduces the prohibition against using false weights and measures in business, it commands that we must maintain just scales, weights and other measuring utensils: “Mozeneh Sedek, Abneh Sedek, Efat Sedek, Ve’hin Sedek Yiheyeh Lachem” (Vayikra 19:36). This verse establishes the affirmative command to ensure that all instruments for weighing and measuring are perfectly calibrated so they give an accurate reading. This verse concludes, “I am Hashem your G-d, who brought you out of the land of Egypt” – which the Sages understood to mean that we were brought out of Egypt to be honest and upright. This command to maintain accurate weights and measures is regarded with special severity, and is even considered the purpose for which G-d brought us out of Egyptian bondage. Additionally, the Midrash explains, the Exodus is mentioned in this context to remind us that on the night when Beneh Yisrael left Egypt, G-d killed all the firstborn of Egypt. He knew exactly which Egyptians were their father’s firstborn children and which weren’t. Certainly, then, G-d knows when somebody tampered with his weighing or measuring device to cheat his customers. The Midrash mentions specifically the practice of crooked merchants to store their scales in salt, which affects the scales such that they make the merchandise seem heavier than it is. The Sages established that scales may not be made from metal, because they eventually rust, such that their reading becomes inaccurate. Additionally, it is forbidden to measure a liquid when it is hot, because it then has foam which makes the volume seem higher than it really is. The Gemara in Masechet Besa (29a) tells of a righteous merchant named Abba Shaul Ben Botnit who followed a number of procedures in order to ensure the accuracy of his measurements. When he measured liquid for his customers, he waited until all the foam settled, so that he would not cheat his customers to even the slightest extent. And when selling oil, he would turn the containers upside down and let them drip throughout the night to ensure that the customers receive every drop to which they were entitled. Many customers did not have the patience to wait for all the foam to settle, and ended up taking less than they were supposed to. Abba Shaul stored the small portion of liquid which they did not take, until he collected 300 barrels’ worth. He decided to donate all this liquid to the Bet Ha’mikdash, as he did not want to benefit from this excess. Rabbinical courts had the obligation to appoint enforcement agents to conduct inspections of merchants’ weights and measures, to ensure that they are accurate. These agents had the authority to punish those whose weights and measures were faulty. The Torah here requires using “Hin Sedek” – an accurate measure of a “Hin,” a measurement of volume. The Gemara comments that the word “Hin” can be read as “Hen,” which means “yes.” This verse thus establishes the obligation to honor our word, that when we say “yes” we follow through on our commitments. This Misva applies in all places, at all times, and to both men and women.