In Nathaniel Hawthorne's The Scarlet Letter, the "A" that Hester Prynne wears "richly embroidered" on her bodice represents her sin of adultery, as evidenced by the infant in her arms and her husband's two-year absence from Hester's company.
In this Puritan community in Boston, Massachusetts, Hester has been found guilty of adultery. Generally, the sentence carried out for this crime (in this theocracy) is death. However, Hester's youth and beauty (which they believe has made her give in to strong temptation), and a sense that her husband has probably died making his way to the New World from England, have moved her judges to show "mercy" and allow her to live in shame—for otherwise her sentence would have been death.
At the end of the chapter, as Hester returns to jail, leaving the light and re-entering the darkness, witnesses claim...
...that the scarlet letter threw a lurid gleam along the dark passage-way of the interior.
To look for meaning in this passage, it is important first to define "lurid." The several definitions may leave interpretation open to some debate. Lurid is defined as:
...gruesome; horrible; revolting; or...glaringly vivid or sensational; shocking; or...terrible in intensity, fierce passion, or unrestraint...
So, then, looking at the events that immediately precede the use of the word, based upon witnesses who were Puritans, we may infer some clearer meaning of the passage. Hester Prynne as been brought out of jail, into the bright light, to stand before the entire community—of Puritans. The high-standing religious leaders, including her own minister (Mr. Dimmesdale) have called upon her to divulge the name of the man with whom she committed adultery. Mr. Dimmesdale's plea is seen by onlookers to be especially earnest—exhorting her gently for her salvation as well as that of her adulterous partner:
If thou feelest it to be for thy soul's peace, and that thy earthly punishment will thereby be made more effectual to salvation, I charge thee to speak out the name of thy fellow-sinner and fellow-sufferer!
He explains that she should not remain silent because she pities or loves the man, for remaining unnamed not only prevents that man from facing the guilt of what he has done, but also makes him guilty of hypocrisy.
Hester defiantly proclaims, "Never!" She also pledges to suffer in that man's place rather than give his name. She speaks of the "A," but also of her guilt and her devotion:
It is too deeply branded. Ye cannot take it off. And would that I might endure his agony, as well as mine!
Dimmesdale is amazed:
Wondrous strength and generosity of a woman's heart! She will not speak!
A Puritan might use "lurid" to mean horrible or shocking, for most Puritans were a judgmental (and hypocritical) group that exercised little compassion or forgiveness to others. One who was truly God-fearing might use "lurid" because the "A" glowed with a righteous anger of heaven, in judgment of Hester. However, because Hester is self-sacrificing, the reader may feel that "lurid" actually refers to her passionate commitment to withhold the father 's name.
The Puritans were inflexible and harsh, but Hawthorne wrote in opposition to actions of his own Puritan ancestors, perhaps using Dimmesdale's voice to praise Hester's loyalty to the man she loves. Historically, Hawthorne's research confirmed the use of the red "A" to brand female adulteresses, which he has used here, but seemingly not in judgment.
With the words
It was whispered, by those who peered after her, that the scarlet letter threw a lurid gleam along the dark passage-way of the interior.
the narrator speaks of the manner in which the towns people and fellow villagers of Hester Prynne just cannot cease to come up with myths and legends about her. They see what she did as a carnal sin that breaks with the rules of God and has bad consequences. The villagers are Puritans and lay all of their wrath on a woman who, by their laws, has committed a crime that breaks with the rules of God, though it does not really break with the instinctual rules of humankind.
Since Puritans are all about dogmatic realities and very little about the fundamental realities of life, they make correlations between behavior and spiritual damnation and create psychological damage in what humanisits see as an unavoidable situation.
The letter, of course, is seen by the villagers as a symbol of evil. It is even red and, moreover, Hester has decorated it in a way that it almost looks like she is showing it off. Already the "goodwives" were throwing poison on Hester's name with their sanctimonious accusations against Hester, the letter, and the cause of her imprisonment, displaying the obvious disgust that they felt for her.
Therefore, as Hester goes back into her cell, the villagers claim that the red, shiny letter A that Hester had to create for herself as punishment was actually glowing, as if it was being fired-up from Hades, and onto Hester's chest. This is basically what they believe the letter was doing, and this is proportionate to the myth they create about Hester as Puritans.
Now that her punishment is over, it glows as though it is a badge of honor. She has suffered through her punishment and now holds pride as she is trying to take on the new world and new life with the scarlet letter.