In the last line what is ironic in the speaker assurance that the dutiful need not fear harm?who have failed in their duty to him?a literary answer for "The Chimney Sweeper" by William Blake
Dramatic irony and irony of situation are powerful literary devices for poetry as they enable a poem to suggest meanings without stating them. In "The Chimney Sweeper," William Blake makes very effective use of such irony.
Emotionally charged contrasts and images underscore the ironic understatement of this poem. As the speaker describes little Tom Dacre, whose white hair was shaved as though he were a prisoner, and whose white skin turns black from the soot, the contrast between his life "in a coffin" and his dreams of "an Angel who had a bright key" the irony of the final lines becomes apparent: Only by dying will Tom and the others ever be happy and warm; "doing his duty" of chimney sweeping will kill him and, then, he "need not fear harm."