Final answer:
The excerpts from Martin Luther King Jr.'s 'Letter from Birmingham Jail' demonstrate the use of rhetorical questions and repetition as key rhetorical devices.
Explanation:
Rhetorical questions: "What kind of people worship here? Who is their God? Where were their voices when the lips of Governor Barnett dripped with words of interposition and nullification?"
Repetition: "when you have seen..." This excerpt repeats the phrase to emphasize the impact of witnessing injustices.
Repetition: "But when you have seen vicious mobs lynch..." This excerpt also utilizes repetition to emphasize the experiences of injustice.
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