Paul Froese, a sociologist at Baylor University, argues that if you understand their view of God you have an explanation of why low-income evangelist are voting both their values and their economic interest:
... approximately 31 percent of Americans, many of whom are white evangelical men, believe that God is steering the United States economy, thus fusing their religious and economic interests. These individuals believe in what I call an “Authoritative God.”
An Authoritative God is thought to be actively engaged in daily activities and historical outcomes. For those with an Authoritative God, value concerns are synonymous with economic concerns because God has a guiding hand in both. Around two-thirds of believers in an Authoritative God conjoin their theology with free-market economics, creating a new religious-economic idealism. Nearly one-fifth of American voters hold this viewpoint, signaling that it can be a major political force.
Religious-economic idealism is the belief that the free-market works because God is guiding it. (Its adherents are, of course, not your typical laissez-faire, Ayn Rand devotees.) The popularity of this ideology explains two supposed paradoxes. First, it indicates why some religious working-class Americans have embraced the GOP. It is not that these individuals ignore their class interests, but rather that they believe issues of abortion and gay marriage are linked to whether God is willing to help solve both social ills and their economic woes.
Second, the fact that income does not predict whether an American believes in an Authoritative God indicates that this is not a class-based ideology. Instead, it is a cosmic worldview, which appeals across economic divides. Most clearly, it benefits the wealthy because conservative economic policies tend to favor them. But wealthy Americans with an Authoritative God can also have a religious-like devotion to their economic conservatism. In this way, their economic pragmatism transforms into a type of religious dogmatism. And dogmatism does not bend to changing circumstances and outcomes, so that we can expect believers in religious-economic idealism to cling to laissez-faire policies even when they appear not to work.Here is more.