In addition to participating in demonstrations and rallies, David was frequently heard on black talk radio, 900AM-WURD and WHAT.
He had strong opinions on just about any subject related to African-Americans, especially whatever he considered wrongs that needed righting.
For several years in the '90s, he ran a kind of market selling used everything, at 12th Street and Girard Avenue.
Under the baleful eyes of city inspectors, he peddled - or gave away - used furniture, clothing, gardening tools, old bicycles, and Bibles - lots of Bibles in various translations and languages.
Except for the Bibles, most of his goods would be considered junk by a lot of people, but David could find customers for much of it.
An imposing, big-voiced man garbed in a mink coat, he would thunder, "God is good!" And his customers would return the sentiment, "God is good!" as they walked away with some item from his vast pile of ancient merchandise.
He called his business "Community Treasures From All Over the World."
At the time, he was living above a former pizza shop operated by his late sister, Terri Beale. He had no heat and no hot water. But he insisted he bathed daily in cold water, even in winter. His only companion was a black Labrador named Hannah.
David was very casual about money. If someone couldn't pay for an item, he'd tell him or her to come back when they could.
He said he ignored documents from the city's Licenses & Inspections Department telling him he had to get a license for sidewalk sales and pay the business privilege tax.
"If it ain't got Jesus' name on it," he told an Inquirer reporter in 1996, "it ain't of no interest to me."
David said he committed crimes and served time in his youth, but his sister, Maggie L. "Monique" Latimer, the oldest of a family of four girls and five boys, said she had no recollection of David ever serving time.
"He was a hustler," Monique said. "He always found a way to make money. He would get things and sell them. He would sell all kinds of things.
"He had a very good heart. He always wanted to help his fellow man."
As an activist, David would seek out a demonstration, some conducted by Sacaree Rhodes, who roamed the city looking for wrongs to combat with her special brand of activism.
And there would be that flag.
Rhodes said David thought that carrying the flag was his "sacred duty." She called it his "ancestral obligation."
"Whenever there was a demonstration, rally or meeting having to do with some issue related to the black community, he would be on the scene," said Warrington.
"In a community, there are many roles people assume, whether it is doctor, lawyer, sanitation worker, preacher, teacher or entrepreneur. Some of the roles are bestowed on folks by benefit of employment, education, training or skill level. And, because his role does not fit neatly in the occupation box, his impact should not be overlooked or denied.
"When he unfurled the red, black and green, he was able to elicit the same level of awe that a military color guard could in full uniform.
"David created his role and his role was a significant one as his community mobilized to correct long overlooked issues."
David was a member of Avenging the Ancestors Coalition and Team Pan-African.
He was born in Mantua, to Mary and Miller Devlin. For some years in his youth, he worked for a gasoline service station in West Oak Lane, but most of his life was spent on the fringes of the retail world.
Besides his sister, he is survived by his mother; five children, David, Daniel, Kiana, Demar and Malaya; two brothers, Michael and Willie Devlin, and two other sisters, Mary Fulton and Virginia Devlin.
Services: Were May 30.