Musar sobre Exodo 20:13

And this is the thing about the group of liars - the content of this group is divided into nine sections:
The first section: The lying man that left the Torah and does evil and destroys with the response of his mouth - like one who contradicts his countryman about a deposit or a transfer or the wage of a wage-worker, as it is stated (Leviticus 19:11), “you shall not deal deceitfully or falsely, a man towards his countryman.” And likewise, one who bears false witness against his neighbor; and it is said (Exodus 20:13), “you shall not bear false witness against your neighbor.” And included in this section is deception and fraud in commerce and in partnerships; and it is stated (Leviticus 25:14), “you shall not cheat, one man, his brother.” And it is [also] stated (Psalms 55:12), “fraud and deceit never leave its square.” And he is called a man of iniquity and a ruffian; and he is the heaviest with iniquity from the groups of the evildoers, as we have discussed in the Gates of Fear of Sin (no longer extant). And the characteristics of this man of iniquity are that he winks his eyes and rolls his fingers, as it is written (Proverbs 6:12-13), “A ruffian individual, a man of iniquity, etc. Winking his eyes, etc.”

Many negative commandments refer to theft such as "you shall not steal" (Shemot 20:13, "you shall not rob" Vayikra (19:13), "you shall not oppress" (ibid); "nor deny nor lie one to another" (Vayikra 19:11), "you shall not oppress one another" (Vayikra 25:14), "You shall not push back your neighbor's boundary" (Devarim 19:14). All these are divisions of the laws of theft which apply to many common business transactions and each one includes many prohibitions under it.

לא תגנובו . Here (19,11) the Torah speaks about someone stealing money or other valuables, whereas in the Ten Commandments in Exodus 20,13 the Torah referred to the kidnapping of a person or persons. I find it puzzling why the Torah used the singular, i.e. לא תגנוב in Exodus, whereas in our portion the legislation is formulated in the plural, לא תגנובו. It is also puzzling why the Torah first legislated the prohibition against completely harvesting one's field. We may understand the sequence of "do not steal" as addressed to the multitude, not because so many people may be guilty of this sin, but because of what the sin leads to. Theft leads to denial of the theft, denial leads to other lies in order to cover up the theft; this is turn leads to perjury. Such behavior even if only by a single individual, will give the whole Jewish people a bad reputation because of the multiple sins involved. The Torah warns us against compounding a sin committed by denying it and even possibly confirming such denial by an oath.