Throughout the letter, King makes references that fellow clergymen would be familiar with, making his case in an idiom they will understand. There are references to the Apostle Paul, to Saint Augustine, to Thomas Aquinas, and to Jesus Christ. He also makes it clear that he, like they, wishes to avoid violence, pointing out that his strategy of nonviolence is a much palatable option for southern whites than many black nationalists, who he says have "concluded that the white man is an incorrigible 'devil.'"

King speaks of his concern for the church itself, pointing out that if Christians do not take a moral stand against the evils of Jim Crow, they risk irrelevance:

If today's church does not recapture the sacrificial spirit of the early church, it will lose its authenticity, forfeit the loyalty of millions, and be dismissed as an irrelevant social club with no meaning for the twentieth century.

At the end of the letter, he affirms his brotherhood in the Christian faith with the ministers he is addressing, saying that he hopes "that circumstances will soon make it possible for me to meet each of you, not as an integrationist or a civil-rights leader but as a fellow clergyman and a Christian brother." Much of the letter is spent expressing his disappointment that these men, who he says he expected to support him, have instead chastised and criticized him. In this way, he is both expressing common cause with them as one minister to several others and calling them to think about their duty as men of the faith. This is a constant theme of the letter, reminding them what true Christians have done in the past, and asking them, in not so many words, to consider what position on segregation would be consistent with their religious faith.

King's attempts to associate himself with his critics begins with the salutation of the Letter--"My Dear Fellow Clergymen"--which helps establish two important elements: 1) King is reminding the clergymen who have criticized his actions that he is one of them; 2) He begins the letter with a tone of conciliation, consistent with his adherence to non-violence in all actions, including responding to criticism.  Also in the opening paragraph, King says that their criticisms require an answer because "you are men of genuine good will" and the criticisms are "sincerely put forth."  From a rhetorical perspective, King has quickly established a tone of reasonableness that he carries through the entire letter, even when he has some relatively harsh comments to make about such people as "the white moderate" and his disappointment with the church.

Later in the essay, he is careful to note that their criticism about "our willingness to break laws" is entirely legitimate, which acknowledges not only that their concern is a reasonable one given the circumstances but also allows King to launch into an extended and very logical analysis of just and unjust laws.  During this discussion, King says, "Let us consider a more concrete example of just and unjust laws," a very subtle, but effective, technique to remind his critics that he is talking to colleagues, not adversaries.

Even when King discusses his disappointment with the "white moderate" and the church's response to King's attempts to right the wrongs of racial injustice, he remains reasonable and considerate when he says that if anything he's said "overstates the truth and indicates an unreasonable impatience."  His long discussion of his disappointment with the church is meant to stir in his critics some embarrassment, but he doesn't make this attack in a verbally violent way--his argument is logical, reasonable, and one senses his own feelings of quiet disappointment.   In an important gesture of good will, King asks for their forgiveness if he's overstated his case, again subtly reminding his critics that his letter is written with the same respect and sincerity as their original criticism.