Nathaniel’s Hawthorne’s The Scarlet Letter is a story about how sin imprisons otherwise good people, most importantly Hester Prynne and Arthur Dimmesdale. By discussing the need for a prison on the very first page, Hawthorne immediately sets the groundwork for a comparison between physical imprisonment and spiritual imprisonment—a metaphor that operates throughout the book. Addressing the need for a cemetery and a prison also allows Hawthorne to illustrate the impossibility of creating the perfect human society. No matter how noble and Godly the Puritans are hoping to be, they are still going to have transgressors, and they are still going to grow old and die.
It is worth noting that he refers to the prison as the “black flower of civilized society.” This metaphorical imagery will be repeated halfway through the story when Dimmesdale and Chillingworth have a veiled discussion about how hidden sin affects a person. In this later passage, the cemetery is also mentioned as the place where “black weeds” were growing on person’s grave, a person who was probably hiding some “hideous secret.” This relates directly to Dimmesdale’s character and his fatal predicament, which some consider to be the focal point of the story.
"Some men break the law; others are broken by it."
I took that quotation from an episode of the original TV show "The Fugitive" because I think it expresses a similar point of view that Hawthorne is expressing with his opening chapter of The Scarlet Letter.
Hawthorne agrees with the Puritans that laws and order are necessary to maintain civil order and moral behavior. No matter what high ideals a society might have, it will always have to deal with the old issues of crime and mortality, what Hawthorne calls "frailty" and "woe."
However, he seems to think that sometimes the Puritan laws were too strict. He believes that normally good people--such as Hester Prynne and Arthur Dimmesdale--were driven to their act of "sin" because the social codes were too complex. The reason he calls the prison a "black flower of society" is that maybe overly strict social codes are sometimes the reason for criminal behavior, rather than the cure for it. Sometimes human nature--as symbolized by the rose bush outside the prison, an obvious contrast to the "black flower" of the prison--is good and social rules are either bad or too strict.
To return to my opening quotation, you might say that in The Scarlet Letter, good people did not break the strict Puritan laws, but that instead they were broken by them.