Both William Loyd Garrison and Henry David Thoreau both agreed on the fact that slavery was unjust and a violation of our most basic human rights. However they differed marginally on their ways of opposing.
Most notably Thoreau touched upon slavery in his essay Civil Disobedience. Here he concluded that should a government be unjust we are well within our rights to withhold our obedience. He questions when rebellion is justified, and in the case of him refusing to pay taxes to a government that supported war and slavery, things he found morally abhorrent, he felt justified. His problem with most reformers is the fact that they typically petitioned the government, thus recognizing an authority that it holds over them, and honoring the will of the majority. This is also applied to voting, because it only honored the will of the majority, when it was his view that the individual was the only decider of right and wrong. By simply refusing to pay their quota to the treasury the individual had the ability to not support their government in their decisions, in a clear nonviolent manner.
Similarly Garrison also advocated for nonviolent protests, and stressed passive resistance. He also called for immediate emancipation of all slaves, and said they could assimilate properly. Garrison was viewed as one of the most outspoken radical abolitionists, despite his passive resistance tactics. Whereas Thoreau was viewed as a spokesperson for abolition, he mostly restricted his help to the cause to the local and individual level, while Garrison published 1,820 issues of the Liberator. Garrison was more interested in reaching the majority of people in the farthest reach he could obtain.
The main characteristic difference we can find between the two despite their major similarities is Thoreau’s stress on the individual and resistance to the government. Although Garrison opposed slavery, he wrote as if pleading the government to make changes, where Thoreau was more inclined to just disregard the governments authority until they earned his disobedience. Garrison was moved to devote all of his energy and resources to a tireless crusade for abolition.