Shulchan Aruch of Rabbi Shneur Zalman of Liadi, Volume 12: Choshen Mishpat

Likkutei Sichos, Vol. 27, pp. 151-152, the Rebbe explains why concern is shown for discrepancies in measures that would usually be considered as insignificant. Measuring implies that a person desires that the transaction be exact and — by using an inaccurate measure — the person uses that very activity to deceive his colleague.

As stated there (ibid.:11), the obligation to return the article or the money applies only when both parties are Jewish. Although it is forbidden to deceive a gentile regarding the value of merchandise, it is not forbidden to take advantage of an error the gentile makes on his own.

Weights should be made in denominations of a litra, 51 half a litra, and a fourth of a litra. 52 One should not make them a third of a litra, a fifth of a litra, or three fourths of a litra, because errors can be made in such instances.53

One must be exceedingly careful about [verbally] abusing one’s wife, refraining from causing her discomfort through words.169 Since she is prone to tears, retribution for [such] abuse comes speedily. A person should always be careful with regard to his wife’s honor, for blessing is found in a man’s house only because of his wife.170 Our Sages169 to

Similarly, [it is prohibited to make other] statements that [generate] emotional pain even though one does not shame [the person by mentioning] his present faults and shortcomings, nor call him by a derogatory name, nor embarrass him in public.

It is permitted to separate the waste from beans and legumes so that [the produce] will appear attractive to a purchaser.113 It is not considered as if [the seller] is misleading him, because this is an obvious matter.114 The purchaser can look [at the produce offered for sale] and determine the degree that its value has increased because the selle

public, so that he will not be shamed. Even in private,151 he should speak to him patiently and gently and refrain from speaking [so] harshly to him [that] he becomes shamed,152

The rationale is that in this instance, his motivation is not to impress his friend — which is deceptive — but to create a favorable impression of his friend in the eyes of others.

“Measures of distance” refers to the measurement of land3 for partners who seek to divide [land they own jointly]. One should not measure for one in the rainy season and for the other in the summer. For in the rainy season, the measuring rope is moist and it will stretch. In the summer, because it dries, it contracts. [Similarly,] one must be preci