When the Defarges return home that evening, they receive information that an Englishman named John Barsad has been sent to spy on them. Madame Defarge promises to add his name to her knitting. Defarge admits to his wife that he's tired and doubts the Revolution will come during their lives. Madame Defarge counters that the Revolution is like an earthquake: it builds slowly, but when it comes it releases catastrophic damage. She says she is content to wait, and will act when necessary.
For all his revolutionary zeal, Monsieur Defarge also has some sympathetic human attributes. Madame Defarge, on the other hand, is tireless and merciless. Her comment suggests just what the Revolution will be like when it comes: not a controlled political action with rational goals defined by political ideals, but a vengeful riot.
John Barsad enters the shop the next day. In conversation with the Defarges, Barsad comments on the plight of the people, trying to get the Defarges to reveal their revolutionary sympathies. Wise to his scheme, the Defarges reveal nothing.
John Barsad the spy has already been spied upon. Suspicion and surveillance are in full swing.
Barsad changes tactics. Knowing that Defarge was once Dr. Manette's servant, he mentions that Lucie is now married to Charles Darnay—who is in reality the nephew of the Marquis Evrémonde. After watching the impact of this news, Barsad leaves.
Because Charles and Lucie bring together opposite sides of the French political divide—nobility and daughter of a revolutionary hero—their marriage provokes anger on both sides.
Defarge is in disbelief. He feels a deep anxiety when Madame Defarge adds Charles's name to her knitting.
To Defarge, human connections still mean something. To Madame Defarge, all aristocrats must die, no matter what.