Duty before desire is one of the themes of the novel. Compare and contrast how Charles Darnay and Defarge both put duty before desire in crisis situations

Charles Darnay is definitely one of those that put duty before desire. He could have simply remained where he was and left Gabelle to his own fate. But, Darnay cannot do this in 'good conscience' and so off he goes. Defarge (both Mr. and Mrs.) have been sorely mistreated by the aristocracy and want justice to be done. They are unable to simply live their lives without becoming involved and being part of the 'solution' to the injustices around them.