Law is a system of rules used to govern a society and control the behaviors of its members. In this case, Martin Luther King is charged for breaking a law. King questions the differences between just and unjust laws to justify his actions in Birmingham and the charges of breaking laws willingly. In "Letter from Birmingham Jail," Martin Luther King writes, "How does one determine when a law is just or unjust? A just law is a man made code that squares with moral law, or the law of god. An unjust law is a code that is out of harmony with the moral law. To put it in the terms of St. Thomas Aquinas, an unjust law is a human law that is not rooted in eternal and natural law." Segregation laws and policies were part of the Jim Crow laws. Some examples of these laws were the segregation of public schools, public transportation, restaurants, and drinking fountains for whites and blacks. For months, an organized boycott of the city's businesses owned and operated by whites had failed to achieve any significant results, leaving King and others convinced they had no other options but more direct actions, ignoring a recently passed law that prohibited public gathering without an official permit. .
For King, this would be his 13th arrest and would become one of the most important of his career. King describes how he and his organization acted responsibly by following four basic steps: 1. Collection of the facts to determine whether injustices are alive; 2. Negotiation; 3. Self-purification; and 4. Direct action (109). King states "any law that uplifts human personality is just. One has not only a legal but a moral responsibility to obey just laws."(107) King was referring to ethics. Ethics questions what the best way for humans to live is, and what kinds of actions are right or wrong in particular circumstances. According to Thoreau Henry David "The practical reason why, when the power is once in the hands of the people, a majority are permitted, and for a long period continue, to rule is not because they are most likely to be in the right, nor because this seems fairest to the minority, but because they are physically the strongest.