In Parshat Ki Tetzei we learn about mitzvot that assure a fair and honest society as God abhors dishonesty.
In Dvarim 25:13-16 we read:
You are not to have for yourself in your pouch varying weight stones (ehven), large and small. You shall not have in your house varying measures (eifah), large and small. A fully accurate, just weight, you shall have, you are to have whole and honest measures; in order that you live long on the Land that HaShem, your God is giving you. Because HaShem, your God’s abomination, are all who do these things; all who do falsehood.
Sforno comments: After having mentioned the ways in which the benevolent presence of the Shechina (Divine Presence) can be assured for the Jewish people, the Torah reminds us that God will not tolerate corrupt justice. God does not even want us to own or keep instruments which are designed to be used in a corrupt, deceptive, manner, so that even without putting these instruments to use the owner/keeper has become guilty of violating a negative commandment.
Dvarim 25:17 states the famous verse: “Remember what Amalek perpetrated against you on the way when you went out of Egypt.”
Rashi explains why Amalek appears here: If you are deceitful with your measures and weights, you should dread harassment from the enemy as we learn in Mishlei 11:1: “Deceitful scales are an abomination to God, but a perfect weight is His desire” and in the following verse: “When pride comes, then comes shame…”
In Mishlei 20:23 we are taught: “False weights and false measures are an abomination to God and scales of deceit are not good.
Unfortunately there are many “religious” people who do not conduct themselves properly when engaging in business transactions. Therefore it is necessary to reread these passages every year. It should not only be about avoiding getting caught by the authorities, it should be about following the mitzvot between a person and God as well as following the laws between a person and their fellow person.
Even though most business today is no longer conducted with weights and scales and even cash is becoming a thing of the past, the same logic still applies. We must not cheat our fellow person!