The House of Mirth presents an antithesis between money and morality. The richest characters, members of New York society's upper echelon, are petty and devoid of scruples, while those in the working class (or at least absent from the circles of the obscenely wealthy) rank high on the moral scale. Main character Lily Bart experiences a transformation through the course of the novel from materialistic and amoral to poverty-stricken but righteous. Many of the novel's conflict-ridden decisions come down to a question of priorities: be good, or be wealthy? It's clear from Wharton's tone that the author condones the former as the better choice.
The ability to differentiate between "dinginess" and immorality constitutes Lily's moral awakening in House of Mirth.