Mayor Marion Barry, who often depicts himself as a David in search of four more years to slay the Goliath of social injustice, found himself on the receiving end of a few well-slung stones last night that were hurled by two other mayoral candidates who seem to think they are David, too.

"Can we stop the clock?" asked Mattie Taylor, a former school board member, when Barry arrived at a Ward 8 candidates forum 50 minutes late. "It's kind of distracting to have a million-dollar incumbent enter in the middle of your speech."

Taylor, whose campaign fund-raising efforts have been outstripped 100-fold by Barry's, drew laughter from the 80 persons who attended the event, sponsored by the Ward 8 Democrats.

But it was Barry -- arriving with an entourage of campaign aides, police security officers and members of his Youth for Barry organization -- who indelibly imprinted the campaign event with the trappings of his political strength.

The Youth for Barry youngsters, who make up a campaign organization that parallels his extensive adult network, led the cheers for "Four More Years" before Barry spoke.

And it was youngsters enrolled in Barry's centerpiece Summer Youth Employment Program who assisted the forum organizers in distributing leaflets that advertised the Democratic event, according to Erica E. Tollett, president of the Ward 8 Democrats.

Taylor, Barry and Calvin Gurley -- the third Democrat who is vying for the party nomination in the Sept. 9 primary -- repeatedly struck themes aimed at the problems associated with Ward 8, the city's poorest area.

"I have learned that I can walk with kings and queens and not lose the common touch," Barry said. "I can have dinner at the British Embassy wtih Prince Charles and Lady Di and then come back to Valley Green public housing project and be just as comfortable."

Barry's handling of housing issues drew the strongest criticism from Gurley and Taylor. Gurley devoted much of his 10-minute opening speech to a slide show depicting boarded-up houses in the District, and both challengers attacked the mayor on the rent-control issue.

Asked whether he favored rent control, Barry said he was "firmly for rent control," but added, "I am not to the point where you are going to drive owners of property out of the market."

Taylor recalled that Barry led the campaign last fall against a referendum aimed at rolling back the city's new rent-control law to bring it in line with the previous, more stringent law.

"I don't know why he says he is for rent control," Gurley said.