Lisa Keister was born poor. “I cleaned houses when I was 10 years old,” she says. Now a professor of sociology at Duke University, she’s trying to understand what leads people not to build wealth. Her answer? Their religious beliefs—at least in part. In a recent study, she finds that both black and white conservative Protestants are among the poorest Americans because they believe that their money belongs to God. As a result, “they tend to seek divine guidance in making important decisions, avoid excess accumulation, and favor using money to support religion,” she writes in the March 2008 American Journal of Sociology.

Using two large national studies, Keister first replicates the decades-old finding that conservative Protestants have less wealth than other religious groups—partly because they have less education, more children whom they bear at younger ages, and fewer women in the workforce. She then adds a new twist, documenting that conservative Protestants more strongly endorse statements such as “The purpose of church is to give money back to God,” “Money is the root of all evil,” and “I think a great deal about the connection between religion and personal finances.” Compared to people of other faiths, they give the highest proportion of their incomes to religious groups.

The strength of people’s religious beliefs and the frequency of their practice “don’t really matter,” finds Keister. Instead, merely growing up in a particular faith strongly shapes people’s saving habits. Moreover, black and white conservative Protestants show similar beliefs and behaviors.

Keister’s data came from more than 6,000 respondents to the National Longitudinal Survey of Youth (NLSY), which followed a cohort of U.S. residents from 1979 until 2000. She also used data from 2,013 respondents to the Economic Values Survey. In 2000, finds Keister, conservative Protestants in the NLSY data set had a median net worth of $26,000, whereas the sample as a whole had a median net worth of $66,200. These differences were due more to conservative Protestants’ failure to accumulate assets over time than to their starting out with less wealth.

Conservative Protestant denominations—which include Assemblies of God, Baptist, Church of God in Christ, Churches of Christ, Nazarene, and Pentecostal—accept the Bible as the inerrant word of God. And in that text they find much ado about money: 10 percent of New Testament verses are about finances, reports Keister. “[Jesus] spoke about money and possessions more than heaven and hell combined,” writes Randy C. Alcorn in his 2003 book The Law of Rewards. At least 25 percent of the U.S. population belongs to a conservative Protestant denomination.

In her studies, Keister focuses on wealth, which is a household’s total assets minus its total liabilities. “To understand poverty, it’s OK to study income, but it’s really important to study wealth,” she says. Without wealth, “if there’s a financial crisis, you’ve got nothing to fall back on. If you remember Hurricane Katrina, there were a lot of people who didn’t have $40 to rent a car and drive away.”

She concludes, “Inequality is at least partially explained by religiosity.”

Read more stories by Alana Conner.