King addresses this letter, composed in a jail in Birmingham where he was imprisoned for his protest efforts, to his fellow clergymen who had criticized those efforts. This audience is important in understanding some of the comparisons King chooses to illustrate the need for his actions in Birmingham.
The clergymen had labeled King's efforts as "extreme." King is initially discouraged by this label but comes to consider it a compliment as he points out to them some other people who have been labeled extreme, as well:
- Jesus was an extremist in love.
- Amos was an extremist for justice.
- Paul was an extremist for the gospel of Christ.
- Martin Luther was an extremist.
He then points to other non-religious examples of positive extremism:
- John Bunyan was an extremist.
- Abraham Lincoln was an extremist.
- Thomas Jefferson was an extremist.
By drawing these comparisons, King compels his audience of clergymen (and later a much larger audience following the publication of the letter) to consider that sometimes extreme efforts are needed and can produce a positive change. He mentions that he is thankful for the "white brothers" who understand the struggle and reach out in meaningful ways to help, from sitting with him on freedom rides to sitting in with him at lunch counters. King explains that these whites "have recognized the urgency of the moment and sensed the need for powerful 'action' antidotes to combat the disease of segregation."
Through these comparisons of extremists, King aligns himself with powerful world changers who influenced history in positive ways, deflating the intended derogatory impact the label was supposed to have on him and his efforts.