People
Virtue would not make such advances if there were not a little vanity to keep it company.
— François de la Rochefoucauld · Moral Maxims and Reflections, no. 201

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
A wry suggestion that goodness gets a lot of its momentum from wanting to be admired. Virtue is pictured as a traveller who moves forward more eagerly with vanity as a companion. It's a sly way of saying that even our best behaviour is rarely completely pure in motive.
Context reviewed