In his "Letter from Birmingham Jail," how did Martin Luther King describe the purpose of nonviolent direct action?

Martin Luther King Junior wrote a letter from Birmingham City jail which glorifies the effect of nonviolent ways or strategies to fight against the racism that was existing.

Explanation:

In his letter he also appeals to the people that it is the duty of people to fight against the unjust laws or injustice that is there going through instead of waiting for justice and non-biased result to Come through the courts.

In the letter he asks the people to Fight for their rights by protests, Marches and sit ins without any violent strategy to be followed.