Argumentum ad lazarum or appeal to poverty is the informal fallacy of thinking a conclusion is correct solely because the speaker is poor, or it is incorrect because the speaker is rich. It is named after Lazarus, a beggar in a New Testament parable who receives his reward in the afterlife.
This is popularly summarized as the statement, "Poor, but honest."
The opposite is the argumentum ad crumenam.
Some experimental evidence supports the appeal to poverty. A 2017 study by Igor Grossmann and Justin Brienza at the University of Waterloo in Canada found that when "wisdom" is defined as the ability to consider opposing perspectives and find a compromise that defuses an interpersonal dispute, poor and working-class people are more likely to show such an ability compared to those in higher socioeconomic classes. As with all fallacies though, the tendency is not absolute.