This week’s Torah portion, Ki Teitzei, contains a commandment that sounds remarkably modern:

“Thou shalt not have in thy bag diverse weights, a great and a small. Thou shalt not have in thy house diverse measures, a great and a small.” –Deuteronomy 25:13–14

The Torah is describing an ancient marketplace. A merchant cannot keep one weight for buying and another for selling, choosing whichever benefits him.

But the commandment reaches far beyond stones and scales. It is about maintaining two versions of the truth.

Today, the second weight might be a spreadsheet, a rent roll, an appraisal, a tax return or a loan application. It might be one set of books showing how a business is actually performing and another presented to the bank. It might even be one transaction reflecting what was actually paid for a property and another showing the lender a different price.

The technology changes. The commandment does not.

That message has become uncomfortable in light of recent financial fraud cases involving members of Orthodox Jewish communities. The Real Deal has documented mortgage schemes involving inflated financial statements, false rents and properties represented at different transaction prices to lenders.

But those cases are only a contemporary illustration of a problem the Torah identified thousands of years ago.

“A perfect and just weight shalt thou have; a perfect and just measure shalt thou have” – Deuteronomy 25:15

The word “perfect” matters. Judaism demands extraordinary precision. We measure the dimensions of a sukkah. We calculate when Shabbat begins and ends. We examine the letters of a Torah scroll and mezuzah. We measure matzah and wine.

The Torah demands that same precision in business.

An observant Jew cannot be meticulous about measurements in the synagogue and casual about numbers in the office. An accurate set of books is also an expression of religious observance. So is an honest closing statement. So is giving the bank the same numbers that describe the actual business.

Perhaps that is why the Torah says not merely that we should not use two different weights. It says we should not have them. Neither outside the home nor inside.

Do not create the second ledger. Do not prepare the alternate transaction. Do not keep a different measure available for when it becomes convenient.

The Torah then uses unusually strong language:

“For all that do such things, even all that do unrighteously, are an abomination unto the LORD thy God.” – Deuteronomy 25:16

There is no exemption because everyone does it, because the bank can afford it, because the loan will probably be repaid or because manipulating the numbers has become customary.

Ki Teitzei offers a simple accounting principle for a complicated financial world: integrity.

The Torah does not ask whether the numbers balance. It demands that they are true.