What does this mean? (easy)

i was arrested friday on a charge of parading without a permit. now there is nothing wrong with an ordinance which requires a permit for a parade, but when the ordinance is used to preserve segregation and to deny citizens the first amendment privilege of peaceful assembly and peaceful protest, then it becomes unjust. ~martin luther king jr.

(“letter from birmingham jail”
paragraph four)

In this excerpt, Martin Luther King is saying that he was unjustly arrested. Although Mr. King was in a parade that was not allowed to happen, he was doing something right by law. The first amendment argues that people can organize themselves into parades and peaceful demonstrations. Who arrested Mr. King broke the first amendment just to prevent people from fighting for the end of segregation.

That is, in the end Mr. King was arrested, but who was committing a crime,  was the officers who arrested him and they were free.

1. temperance, abolitionist, suffragist