In the crowd, several delegates held up bumper stickers with versions of that slogan.
But with stubbornly high unemployment and the economy the driving factor in the presidential race, Biden acknowledged many Americans were not yet feeling things had improved since Obama won the White House in 2008. He asked for patience.
"Yes, the work of recovery is not yet complete, but we are on our way," Biden said. "The journey of hope is not yet finished, but we are on our way. The cause of change is not fully accomplished, but we are on our way. So I say to you tonight, with absolute confidence, America's best days are ahead, and, yes, we are on our way."
Biden also spoke plainly about the respect he has developed for Obama during the past 3 1/2 years, particularly the president's hands-on approach to foreign policy. The two sometimes have disagreed, but that has only increased Biden's standing with Obama, who appreciates discussion over dictating decisions. On days they are both on White House grounds, they spend some four hours together in meetings; Biden often is the last person Obama consults on major decisions.
"I want to take you inside the White House to see the president, as I see him every day," Biden said. "Because I don't see him in sound bites. I walk down the hall, 30 steps to into the Oval Office, and I see him, I watch him in action."
"He always has the courage to make the tough decisions," Biden added.
Biden has been an occasional headache for Obama, though. On the day Obama signed the Democrats' health care overhaul into law, Biden stole headlines by using an expletive in range of a live microphone. He forced Obama's hand on gay rights during an interview that sped up the president's endorsement of gay marriage. And more recently, to an African-American audience in Virginia, he said of Republicans, "They're going to put y'all back in chains."