John Stauffer, The Black Hearts of Men: Radical Abolitionists and the Transformation of Race (Cambridge: Harvard University Press, 2002), 255-256.
Although the outcome of the raid would undoubtedly have been the same, more blacks might have come to his aid had Brown’s timing been better. Almost every analysis of the raid asserts that slaves and free flacks ignored Brown’s efforts on their behalf, but some evidence – much of it stemming from oral tradition – suggests that free blacks in Jefferson County and throughout the North and Canada knew of Brown’s plans and were prepared to join him. Brown originally scheduled the raid for July 4, 1858 (reflecting his fondness for symbolic value), but the date was postponed when one of his comrades, Hugh Forbes, turned traitor and threatened to expose the raid unless he received money…Evidently, his attack caught a number of his allies by surprise: Richard Hinton was in nearby Chambersburg “at a black-operated underground railroad post,” awaiting word to join Brown. Harriet Tubman, was trying to recruit followers. And a group of blacks from Ontario, Canada, were near Detroit, and supposedly on their way to join Brown.