Craig Keener in his massive work (about 900 pages) spends a significant section responding to Hume’s argument that miracles cannot have happened. One aspect of Hume’s argument is that miracles that only those from “ignorant and barbarous nations” could believe in miracles. Keener then shows how Hume’s argument at this poitn is based upon a virulent racism (to get the full weight of Hume’s ugliness on this point, see his essay, “Of National Characters”).
Keener demonstrates the vile racism of Hume and then shows Hume’s racism is part of Hume’s argument against the possibility of miracles:
“Hume’s prestige assigned his opinions a public weight far heavier than they merited, even on issues like miracles and race that were outside his expertise. Hume’s influence in bolstering racist sentiments proved substantial; thus, for example, philosopher Immanuel Kant declared that blacks had inferior mental capacities and “by nature no feeling that rises above the trifling.” He explicitly cites Hume’s challenge, noted above, to find any of “the hundreds of thousands of blacks,” even among those who have been freed, who became intellectually great. “The blacks are very vain,” he concluded, “but in the Negro’s way, and so talkative that they must be driven apart from each other with thrashings”.
“Lest we suppose that Hume’s misinformed approach lacked further practical consequences beyond the world of ideas, his words proved useful for the arguments of pro-slavery authors, who cited his authority on the question regularly. Writers who opposed racism were forced to respond to Hume, as in the 1770 essay of James Beattie or the 1784 essay of James Ramsay that proved of crucial importance in the British abolition movement. Unlike Hume, who had little genuine experience with slaves, James Ramsay spent nineteen years on a Caribbean island with thousands of slaves and therefore offers a wider range of experience than the more publicly honored Hume. That Hume’s opinion carried more weight in many circles is tragic. Hume was a child of his day, but his argument against trusting testimony for miracles based on its presence among “ignorant and barbarous nations” should never again be admitted; its origins are inseparable from his ethnocentrism”
Keener, Miracles, pp 224-5.