I have a degree in economics and an MBA, and let me tell you what you’ll never hear from an economics professor: “You want to get rich? Give away your money.”

It doesn’t make any economic sense.

You have to first have money. Then you can give it away.

That’s why economist Arthur Brooks was so skeptical when entrepreneurs kept telling him that the number-one reason for their wealth was their giving.

He didn’t buy it. So he set out to disprove it.

Brooks analyzed data from 30,000 American families across the country and discovered something that shocked him: The more people gave, the more they earned.

Confused by the findings, he zoomed out and looked at charitable giving and income across the entire United States over a 50-year period. Same result.

Giving didn’t just follow prosperity; it created it.

Brooks calculated that if Americans increased private charitable giving by just one percent—about $2 billion a year at the time—it would generate roughly $39 billion in additional economic output.

Frustrated, he left the halls of economics and turned to a colleague in the psychology department.

“I’m getting this result that I can’t understand,” he said. “It doesn’t make sense. It’s like the Hand of G‑d is in the economy, and I just can’t believe it’s true.”

His colleague had a good laugh.

After all, Brooks was known to be a religious person.

“Yes,” Brooks explained, “but I’m an economist too! We’re not supposed to believe these things. I need a more earthbound explanation.”

“I’ll give you one. We’ve known for decades in the psychology field that people who give become happier. Does that help?”

Suddenly, it clicked.

As a business-school professor, Brooks knew that happy people are more productive.

Giving leads to happiness. Happiness leads to productivity. Productivity leads to more wealth.1

Giving is a wealth multiplier.

Almost 30 years ago, as a fresh economics graduate working on Wall Street, I would have shared Brooks’s initial skepticism. Had I learned about his discovery then, I would have been shocked. Today, I’m not.

Long before economists ran regression analyses, the Torah codified the reality Brooks had discovered in a financial framework—one designed to both generate and protect wealth.

Now clearly the Torah’s promise is not dependent on happiness and productivity, but this demonstrates that even science confirms what we knew all along.

We have a mitzvah of maaser: giving 10 percent of our earnings to tzedakah.

Not only because it is spiritually and morally sound, but because it is financially sound.

The Talmud interprets the Torah’s words aser te’aser—“You shall surely tithe”—as aser bishvil shetitasher: Give a tenth so that you will become wealthy.

And the Sages add that maaser acts as a protective fence around our wealth.

The deeper I went into the Torah’s approach to giving, the more I realized how precise that financial framework is.

Always practical, Jewish law prescribes a range for our giving. Ten percent is the standard minimum, and up to 20 percent—what is known as chomesh—is the ideal fulfillment of the mitzvah. At the same time, the Sages generally caution us not to give more than 20 percent, lest we give away so much that we eventually need to receive tzedakah ourselves.2

The Torah’s financial framework, therefore, prevents us from giving too little or too much.

But I began to wonder: Why that range—10 to 20 percent? Why not 5 to 10? Or 8 to 16? Was there something significant about the 10-to-20-percent range?

This time, I was the one looking for an earthbound explanation.

During my research, I came across a 17th-century Jewish manuscript called Sefer HaGan V’Derech Moshe, in which the author says he consulted experts in funnel design.

They told him that for a funnel to function properly, the opening of its neck had to be at least one-tenth the diameter of the top. One tenth. Ten percent.

A funnel?

I’m no physicist, but if a rabbi in the 1600s was comparing notes with funnel experts, I figured this was worth investigating.

So I did what any modern-day researcher does. I asked ChatGPT. I’m kidding. First, I went to my engineer friends, who told me there might be something there. Their answers sent me down an internet rabbit hole investigating something called Torricelli’s Law.

Never heard of it? Neither had I.

After an exhausting dive into Torricelli’s formulas—gravitational acceleration, volumetric flow rate, all of it—I landed on even more than I was expecting.

What I found suggested that the optimal opening of a funnel—the one that allows for continuous, stable flow—is between 10 and 20 percent of the funnel’s outer diameter.

Below 10%, liquid backs up and spills. Above 20%, everything rushes through and nothing is retained.

Suddenly, the Torah’s numbers made sense.

We are the funnel!

We receive bounty from G‑d. As long as we allow some of that bounty to flow through us, giving it to others — in the right proportion — G‑d continues to pour income.

Ten to twenty percent isn’t arbitrary, nor is it optional—unless, of course, you don’t care about your money.

And that’s the piece most people are never taught.

Giving isn’t just charity; it’s strategy.