The major difference between the Social Gospel and the Gospel of Wealth is that the former saw the rich as something of a source of societal problems while the latter saw them as the source of solutions to the social problems.
Both gospels acknowledged that there were problems in society. The Social Gospel argued that many of the problems in society came about because the rich were abusing the poor. They felt that things like unrestrained capitalism created conditions that made the poor worse off. They felt that all people should act in more Christian and egalitarian ways. This would solve many of society’s problems.
By contrast, the Gospel of Wealth argued that the rich were the ones who could best solve society’s problems. The rich were (as Social Darwinism tells us) the fittest people. Therefore, they should essentially take care of the other, less fit people. They should use their money to help those people, but they should retain complete control of the money because they (more than the poor or the government) knew best how to use the money for the benefit of society.
The Wealth Gospel favored industrialists over the average citizen. For example, proponents of the Wealth Gospel (such as Andrew Carnegie) rejected any type of government intervention in the economy and supported unfair policies that disproportionately benefited industrialists.
Carnegie favored lassez-faire economics, which was central to the Wealth Gospel. This is the belief that government should only interfere in the economy to protect life, property, and individual freedom. Proponents of the Wealth Gospel differed from those of the Social Gospel in that they rejected even government aid to the poor. Carnegie himself favored what he called "indirect philanthropy." Instead of giving direct aid to the poor (in the form of food aid or unemployment benefits) as the proponents of the Social Gospel suggested, men like Carnegie preferred to build libraries for the poor.
Like his fellow proponents of the Wealth Gospel, Carnegie believed in the Darwinian "survival of the fittest" philosophy. Each man was responsible for his own success in life, and only the strongest would attain wealth. Poverty was primarily regarded as the result of one's moral and personal failings. Social Darwinists who favored the Wealth Gospel also saw the high rate of infant mortality and widespread disease as a form of "culling." The weak had to be eliminated to make room for the strong. Men like Carnegie favored industry and tenacity; they made no allowances for misfortune and individual differences in physical and mental ability.
Unlike the proponents of the Wealth Gospel, proponents of the Social Gospel favored government intervention; they maintained that government intervention was needed to protect workers from systemic abuse by industrialists bent only on amassing profit. During the Industrial Revolution, working conditions in the factories were deplorable. Children worked long hours in harsh conditions. Many stood for 10-14 hours at machines and were forced to breathe in toxic fumes that endangered their health. These children also earned meager wages for their work.
In fact, the Social Gospel movement became the basis for the Progressive Movement. Many who believed in the Social Gospel believed in the Protestant concept of caring for the poor. Soon, social justice warriors like Jane Addams and Grace Abbott spoke up and agitated for the rights of children and workers in the factories. Proponents of the Social Gospel were also responsible for the building of settlement housing and the introduction of low cost health-care to the poor. In all, the Gospel of Wealth differed from the Social Gospel in terms of its approach towards wealth, government, and the rights of the working poor.
Source: The American Dream vs. The Gospel of Wealth by Norton Garfinkle.