Frances Harper (1825-1911) was an African-American poet who was involved in the movement to abolish slavery. Her poem "Bury Me in a Free Land" is clearly an anti-slavery statement.
The speaker in the poem says that she is willing to be buried anywhere, even among "earth's humblest graves," as long as she is not buried "in a land where men are slaves."
The speaker describes some of the horrors of slavery: lashings, "babes torn from [their mother's] breast," bloodhounds seeking fugitives, and young girls being sold "from their mother's arms...for their youthful charms."
The speaker says that she could not rest in a place where such things take place; if she saw them from her eternal resting-place, her "eye would flash with a mournful flame, / [Her] death-pale cheek [would] grow red with shame."
Similar to the outlook of many slaves, the speaker does not see any practical solution to the slavery problem. Rather, she seeks refuge from the problem in the afterlife.