Final answer:
Dr. King's central idea is the moral duty to oppose unjust laws. He develops this with his own arrest example and historical references, distinguishing legal action and moral righteousness.
Step-by-step explanation:
Dr. Martin Luther King Jr.'s central idea in the excerpts from "Letter from Birmingham Jail" is that there is a moral responsibility to disobey unjust laws. The specific details that develop this idea include King's own arrest for parading without a permit, which he argues was a misuse of legal power to maintain segregation (paragraph 4). He further elaborates that willingly accepting the penalty for breaking such laws can demonstrate the highest respect for law (paragraph 5), and uses historical references to underpin his argument, such as the legal activities of the Nazis and the illegal efforts of the Hungarian freedom fighters (paragraph 6). These examples illustrate the distinction between what is legal and what is moral, clearly supporting King's assertion that laws that contravene ethical principles, like segregation laws, must be challenged.