Barack Obama is not the subject of “Quest,” Jonathan Olshefski’s new documentary, an intimate and patient portrait of a North Philadelphia family. But the film, which begins and ends with presidential elections — Mr. Obama’s in 2008 and his successor’s eight years later — is shadowed, in some ways haunted, by his presence and his temperament. At one point, he appears on television, in the wake of the massacre of school children and their teachers in Newtown, Conn. “These neighborhoods are our neighborhoods,” he says, referring to the places that have been devastated by gun violence. “These children are our children.”

The simple inclusiveness of that idea and the feeling behind it — the sense that this nation, with all of its troubles, is something we’re all in together — may sound especially poignant now, and even a bit quaint. But a similar ethic of solidarity informs every moment of “Quest,” which brings us into the neighborhood and the home of Christopher and Christine’a Rainey and their teenage daughter, PJ.

Christopher is also known as Quest, which is the name of the recording studio where he sits behind the mixing boards as local rappers spit their rhymes. Christine’a is Ma Quest, and the two of them, without vanity or any expectation of praise or reward, serve as mentors, confidants and semi-parental figures for the people around them. Mr. Rainey wakes up at dawn to deliver coupon circulars door to door. His wife works long hours at a shelter for survivors of domestic violence. If you lived in North Philly, you would want to know them. “Quest” offers the gift of imagining that you do, even as it honors their complicated, sometimes opaque individuality.