Martin Luther King uses rhetorical devices to write a letter to his critical clergymen, arguing that his actions were not "unwise and untimely". Through techniques such as tone, diction, allusions, and metaphors, King politely provides a rational explanation as to why direct action must be taken immediately.
King uses a polite tone by answering their statement in "patient and reasonable" terms. King, along with several members of his staff, is there because there is injustice. He alludes to the Apostle Paul by explaining that "just as he left his village of Tarsus" he is going outside his hometown. The allusion is used to justify the actions he has taken. If King is wrong in what he is doing, then the Biblical characters he refers to must be wrong in their actions as well. More over, the allusion of Paul places King in a category of important people that are well respected.
King then goes on to list the four basic steps they went through for their nonviolent campaign. This proves that King was very logical and rational in the steps he took towards direct action.
After many months of delays and postponements, King decided their direct action could not be delayed anymore. He uses a metaphor of a mountain to clarify that the tension they create in society will "help men rise up from the depths of prejudice and racism". They have been waiting too long, and there is never a good time for a direct action campaign. He explains that the nations of Asia and Africa are moving with "jet-like speed" toward gaining political independence, yet they still creep at "horse and buggy pace" toward gaining a cup of coffee. By comparing their situation with other world nations, King metaphorically argues that they have been patient and waited long enough. This metaphor backs up his opinion that it's easy for people who haven't experienced segregation to say, "wait". King continues to use his polite tone by saying he "hopes that people can understand the despair they feel and their unavoidable patience".