"There is no -- all you had to do was look at their response to the State of the Union, what were there, three or four? I think we should get a little focused here, let's get a little focused," he added later.
The vice president also heralded the recent passage of bipartisan budget and spending agreements, but warned that Republicans would quickly seek to pass conservative budget and spending proposals rejected in recent years by the Democratic-controlled Senate.
"Does anybody in this room think that the Republican Party has walked away from the Ryan budget? Does anybody in this room think that if they are able to take the Senate or increase their numbers or maintain their numbers in the House that that's not what we're going to get back to?" he asked.
With nine months to go until Election Day, Biden sought to pump up Democrats, who are trailing in generic congressional preference polls and face historical trends suggesting they will lose seats in the sixth year of a Democratic president.
He reminded the crowd: "Between now and November, is three political lifetimes."
"Keep your eye on the ball," he added later. "The American people are where we are. And let’s go out and make every single effort not just to defend, but to aggressively push our agenda. They are with us. They are with us. And I’m sure in hell glad that I'm with you."
Biden was introduced to the crowd by Rep. James Clyburn (D-S.C.), an assistant minority leader and close friend of Biden's, who joked about the vice president's frequent trips to South Carolina, an early presidential primary state.
"Seems every time I turn around I’m bumping into Joe Biden in the Palmetto State," he said, adding later: "He is vying for favorite son status."