Once toe to toe, now shoulder to shoulder.

That was the message Hillary Clinton and Barack Obama drove home as they met for their first joint campaign event Friday, assuring voters that a bruising primary would not stop them from uniting to take back the White House for Democrats.

The carefully choreographed rally, held in the tiny town of Unity, N.H., was the most visible in a series of gestures the two senators have made over the past week to heal the hard feelings of the primary race.

Leery of disenchanted Clinton backers turning from their party in November, the candidates used the event to stress to Democrats directly that the price of disunity is too high, and that it's time to close ranks behind the presumptive nominee.

"To anyone who voted for me and is now considering not voting or voting for Senator (John) McCain, I strongly urge you to reconsider," Clinton told supporters, who took turns cheering “Obama” and “Hillary.”

The candidates have traded kind words and deeds to prove they’re serious.

After Obama met with top Clinton donors Thursday night and assured them he would help pay off her debt, he and his wife Michelle each gave a maximum $2,300 donation to that cause. Then Bill and Hillary Clinton on Friday gave the same amount to Obama's campaign.

Obama's campaign also announced it had hired Neera Tanden, former Clinton campaign policy director, as its new domestic policy director.

On Friday, they said that despite the jabs of the last several months their respect for one another was only strengthened by their historic primary race.

"I've admired her as a leader, I've learned from her as a candidate. She rocks," Obama said. "I am proud to call her my friend."

And Clinton, who during her concession speech three weeks ago spoke mostly of her own campaign, left no doubt Friday that this was Obama's show now. She urged voters to get behind him and create an "unstoppable force" for change.

"This was not a pat on the back for Barack Obama from Hillary Clinton. This was a bear hug," said Kevin Madden, former spokesman for GOP candidate Mitt Romney. "Hillary Clinton seemed to make the case ... to her own voters for Barack Obama, and if they are going to heal the wounds of the primary that is very important."

Nearly 6,000 people gathered in the open fields of the tiny town to watch the two senators embrace.

"I don't think it's at all unknown to this audience that this was a hard-fought primary campaign," Clinton told the crowd. "We have gone toe to toe in this hard-fought primary, but today and every day going forward we stand shoulder to shoulder for the ideals we share, the values we cherish and the country we love."

Speaking somewhat tongue-in-cheek, Clinton described their primary fight as a "spirited dialogue."

Clinton, who returned this week to the Senate, is assuming a new role as top surrogate for the presumptive Democratic nominee. The former rivals kissed and made up Friday morning when they met to take off from Reagan National Airport outside Washington, D.C.

The symbolism of Unity, N.H., wasn't in the name alone. Each candidate won 107 votes there during the state's first-in-the-nation primary.

It was a state Clinton narrowly won on Jan. 8 and the state that set John McCain on course to clinching the GOP nomination. Though it is only worth a few electoral votes, Obama wants to rally Clinton backers and make New Hampshire one of several moderate states across the country where he dominates his Republican opponent.

McCain still has his eye on Clinton supporters.

"I do think that we are able to attract some of Senator Clinton's supporters," McCain said Friday. "I have to get Republican votes, independent votes and the old and new Reagan Democrats."

Both Democrats badly need one another as they move to the next phase of the campaign.

Obama is depending on the former first lady to give her voters and donors a clear signal that she doesn't consider it a betrayal for them to shift their loyalty his way. Clinton won convincingly among several groups during the primaries, including working-class voters and older women -- groups that McCain has actively courted since she left the race.

Clinton, for her part, needs the Illinois senator's help in paying down her campaign debt, plus an assurance that she will be treated respectfully as a top surrogate on the campaign trail and at the Democratic Party convention later this summer.

Click here for a video flashback of the tiffs Obama and Clinton have had over the past several months.

FOX News' Major Garrett and The Associated Press contributed to this report.