By the late 1830s, Emerson had befriended Henry David Thoreau, who had returned to Concord after graduating from Harvard in 1837. In 1841, the younger man joined the Emerson household as a handyman, in which capacity he took care of things that the well-known, much-demanded, and distinctly unhandy Emerson could not. In his biography of his father written for the Second Series of Memoirs of Members of the Social Circle in Concord (1888), Edward Waldo Emerson recalled Thoreau's stable presence, his usefulness about the house and garden, and his particular rapport with children. Whatever distance eventually came between Emerson and Thoreau, Thoreau's friendship was always valued by Mrs. Emerson and her children. Thoreau lived with the Emersons until 1843, and returned to look after things while Emerson made his second trip to Europe, in 1847 and 1848. In 1844, Emerson offered Thoreau the use of property he had purchased at Walden Pond, where Thoreau moved in 1845. In January of 1842, shortly after the death of Thoreau's brother John, the Emersons' first child Waldo died of scarlet fever. The Emersons were overwhelmed with grief. With time, Emerson was able to come to terms with his loss. He later wrote the poem "Threnody" in honor of Waldo.
In the 1830s, Concord was already sensitive to the issue of slavery, but Emerson's involvement in abolition grew slowly. Concord residents took an active part in the Middlesex County Anti-Slavery Society, established in 1834. The Ladies' Anti-Slavery Society of Concord was formed in 1837; Lidian Emerson belonged to it from the beginning. Other members of Emerson's family (his aunt Mary Moody Emerson and his brother Charles) also openly expressed antislavery sentiment in the 1830s. Emerson delivered his first antislavery address in Concord in 1837, in response to the murder of abolitionist publisher Elijah Lovejoy in Alton, Illinois. But his speech disappointed many. It focused not so much on the wrong of slavery as on the right of free speech. It took time for him to overcome equivocal feelings about abolition. He was committed to the ideas of the central importance and the dignity of the individual, but he had difficulty overcoming a sense that slaves had not displayed evidence of a potential for full development. Moreover, like Thoreau, Emerson believed that reform could be effected only through the individual, not through organized movements. Following the delivery of his 1837 speech, Emerson did not speak publicly on the subject again until 1844. He was moved to action only by the steady unfolding of events that, in their threat to the individual and to conscience, could no longer be ignored. Emerson supported the choice of abolitionist Wendell Phillips as speaker for the Concord Lyceum in the early 1840s, despite the objections of conservative community members. By 1844, the annexation of Texas was imminent and Emerson was disgusted with the failure of government and political leaders like Daniel Webster to stop the spread of slavery. He consequently delivered a speech on August 1, 1844, at a Concord celebration of the anniversary of emancipation in the British West Indies. This was much more powerful in its opposition to slavery than had been the 1837 speech, and it placed Emerson among effective public supporters of abolition. The passage of the Fugitive Slave Law in 1850 further fueled his antislavery activism. Throughout the 1850s, he spoke at abolition meetings around the country. He opposed the Kansas-Nebraska Bill, and supported radical abolitionist John Brown (whom he heard speak at the Concord Town Hall in February of 1857).
