"If people use Knives for such purposes, they have to pay for it." comment

I think this is when the spy is talking to Madame Defarge about Gaspard’s execution. Madame Defarge is not sympathetic saying that Gaspard had it comming, “if people use knives for such purposes, they have to pay for it. He knew beforehand what the price of his luxury was; he has paid the price.”