Philadelphia (CNN) President Barack Obama on Wednesday handed his legacy to Hillary Clinton, setting her up for the speech of her life with a powerful endorsement and the enduring image of a warm embrace.

Clinton joined Obama on stage after his speech, and the President and his 2008 primary rival clung together in a shared moment of symbolism: the nation's first African-American leader entrusting its future to the woman who could become its first female commander-in-chief.

Members of the media stand during the event.

Members of the media stand during the event.

Tape on a delegate's mouth makes a statement Monday about the Democratic National Committee. Recently leaked committee emails appeared to show favoritism toward Clinton in the primary race, and many Sanders supporters entered the convention upset. The controversy has caused Debbie Wasserman Schultz to step down as the committee's chairwoman at the end of the convention.

Former pro basketball players Jason Collins, left, and Jarron Collins wave to the crowd. Jason Collins, the first openly gay player in the NBA, said he told the Clintons about his sexual orientation before coming out publicly.

Former pro basketball players Jason Collins, left, and Jarron Collins wave to the crowd. Jason Collins, the first openly gay player in the NBA, said he told the Clintons about his sexual orientation before coming out publicly.

Anastasia Somoza, an advocate for people with disabilities, comes out to speak.

Anastasia Somoza, an advocate for people with disabilities, comes out to speak.

U.S. Sen. Al Franken appears on stage with comedian Sarah Silverman. Franken, of course, has a comedic background as well, having once starred on "Saturday Night Live."

U.S. Sen. Al Franken appears on stage with comedian Sarah Silverman. Franken, of course, has a comedic background as well, having once starred on "Saturday Night Live."

In his speech Monday, U.S. Sen. Cory Booker included a message about togetherness. "Patriotism is love of country. But you can't love your country without loving your countrymen and countrywomen," he said.

In his speech Monday, U.S. Sen. Cory Booker included a message about togetherness. "Patriotism is love of country. But you can't love your country without loving your countrymen and countrywomen," he said.

First lady Michelle Obama gives a speech. "This election -- every election -- is about who will have the power to shape our children for the next four or eight years of our lives," she said. "And I am here tonight because in this election, there is only one person who I trust with that responsibility -- only one person who I believe is truly qualified to be President of the United States. And that is our friend, Hillary Clinton."

First lady Michelle Obama gives a speech. "This election -- every election -- is about who will have the power to shape our children for the next four or eight years of our lives," she said. "And I am here tonight because in this election, there is only one person who I trust with that responsibility -- only one person who I believe is truly qualified to be President of the United States. And that is our friend, Hillary Clinton."

U.S. Sen. Elizabeth Warren talks to the crowd in Philadelphia. "We are not going to be Donald Trump's hate-filled America," she said. "Not now. Not ever."

U.S. Sen. Elizabeth Warren talks to the crowd in Philadelphia. "We are not going to be Donald Trump's hate-filled America," she said. "Not now. Not ever."

Sanders spoke out against Republican nominee Donald Trump and said Clinton must become President. "If you don't believe this election is important, if you think you can sit it out, take a moment to think about the Supreme Court justices that Donald Trump would nominate and what that would mean to civil liberties, equal rights and the future of our country," Sanders said.

Sanders spoke out against Republican nominee Donald Trump and said Clinton must become President. "If you don't believe this election is important, if you think you can sit it out, take a moment to think about the Supreme Court justices that Donald Trump would nominate and what that would mean to civil liberties, equal rights and the future of our country," Sanders said.

Sanders delivers the headline speech on Monday. "I understand that many people here in this convention hall and around the country are disappointed about the final results of the nominating process," Sanders said. "I think it's fair to say that no one is more disappointed than I am. But to all of our supporters -- here and around the country -- I hope you take enormous pride in the historical accomplishments we have achieved."

Sanders delivers the headline speech on Monday. "I understand that many people here in this convention hall and around the country are disappointed about the final results of the nominating process," Sanders said. "I think it's fair to say that no one is more disappointed than I am. But to all of our supporters -- here and around the country -- I hope you take enormous pride in the historical accomplishments we have achieved."

Delegates hold up signs referring to Indiana Gov. Mike Pence, the running mate of Republican nominee Donald Trump.

Delegates hold up signs referring to Indiana Gov. Mike Pence, the running mate of Republican nominee Donald Trump.

Sanders smiles while attending roll call. He moved to name Clinton the official nominee.

Sanders smiles while attending roll call. He moved to name Clinton the official nominee.

U.S. Sen. Bernie Sanders waves to the crowd after the Vermont delegation cast its roll-call votes Tuesday.

U.S. Sen. Bernie Sanders waves to the crowd after the Vermont delegation cast its roll-call votes Tuesday.

"Mothers of the Movement" -- mothers whose unarmed children have been killed by law enforcement or due to gun violence -- take the stage Tuesday.

"Mothers of the Movement" -- mothers whose unarmed children have been killed by law enforcement or due to gun violence -- take the stage Tuesday.

Florida delegate Bernard Jennings holds a cardboard cutout of Hillary Clinton over the face of his young son Ethan on Tuesday.

Florida delegate Bernard Jennings holds a cardboard cutout of Hillary Clinton over the face of his young son Ethan on Tuesday.

Actresses America Ferrera, right, and Lena Dunham walk on stage to deliver remarks.

Actresses America Ferrera, right, and Lena Dunham walk on stage to deliver remarks.

Former Vermont Gov. Howard Dean re-enacts his infamous "Dean Scream" during his speech.

Former Vermont Gov. Howard Dean re-enacts his infamous "Dean Scream" during his speech.

Former U.S. secretary of state Madeleine Albright waves to the crowd after speaking on Tuesday.

Former U.S. secretary of state Madeleine Albright waves to the crowd after speaking on Tuesday.

Bill Clinton arrives on stage to give his speech. In his speech, he portrayed his wife as a woman who tirelessly ran a family and a career. "She always wants to move the ball forward," he said. "That is just who she is."

Bill Clinton arrives on stage to give his speech. In his speech, he portrayed his wife as a woman who tirelessly ran a family and a career. "She always wants to move the ball forward," he said. "That is just who she is."

The former President told the crowd about how he met his wife for the first time. He also called her "the best damn change-maker I've ever met in my entire life."

The former President told the crowd about how he met his wife for the first time. He also called her "the best damn change-maker I've ever met in my entire life."

Former U.S. President Bill Clinton waves to the crowd before giving a speech on Tuesday.

Former U.S. President Bill Clinton waves to the crowd before giving a speech on Tuesday.

Actress Meryl Streep addresses the crowd before Clinton's video message. Streep said Clinton will be the first female President of the United States, "but she won't be the last."

Actress Meryl Streep addresses the crowd before Clinton's video message. Streep said Clinton will be the first female President of the United States, "but she won't be the last."

Clinton appears live on a video screen Tuesday night. Just a few hours earlier, she officially became the party's presidential nominee. She is the first woman to lead a major party's presidential ticket. "I can't believe we just put the biggest crack in that glass ceiling yet," she told the crowd.

Clinton appears live on a video screen Tuesday night. Just a few hours earlier, she officially became the party's presidential nominee. She is the first woman to lead a major party's presidential ticket. "I can't believe we just put the biggest crack in that glass ceiling yet," she told the crowd.

Senate Minority Leader Harry Reid is escorted to the podium by his wife, Landra, on Wednesday.

Senate Minority Leader Harry Reid is escorted to the podium by his wife, Landra, on Wednesday.

People hold up prints that pay respect to those who were killed in the Charleston, South Carolina, church shooting of June 2015. Two survivors of the shooting were speaking to the crowd.

People hold up prints that pay respect to those who were killed in the Charleston, South Carolina, church shooting of June 2015. Two survivors of the shooting were speaking to the crowd.

Former U.S. Rep. Gabby Giffords waves to the audience before speaking on Wednesday.

Former U.S. Rep. Gabby Giffords waves to the audience before speaking on Wednesday.

Broadway performers sing "What the World Needs Now Is Love" on Wednesday.

Broadway performers sing "What the World Needs Now Is Love" on Wednesday.

A delegate wears a Bernie Sanders mask on Wednesday. Sanders finished second to Clinton in the presidential primaries.

A delegate wears a Bernie Sanders mask on Wednesday. Sanders finished second to Clinton in the presidential primaries.

Biden walks to the podium before delivering his speech.

Biden walks to the podium before delivering his speech.

U.S. Vice President Joe Biden also went after Trump, saying "this guy doesn't have a clue about the middle class -- not a clue. Actually, he has no clue, period."

U.S. Vice President Joe Biden also went after Trump, saying "this guy doesn't have a clue about the middle class -- not a clue. Actually, he has no clue, period."

"I understand the appeal of a businessman President. But Trump's business plan is a disaster in the making," said Bloomberg, an independent. He said the Republican nominee is a "risky, reckless, and radical choice."

"I understand the appeal of a businessman President. But Trump's business plan is a disaster in the making," said Bloomberg, an independent. He said the Republican nominee is a "risky, reckless, and radical choice."

Former U.S. President Bill Clinton, right, cheers during the speech of former New York City Mayor Michael Bloomberg.

Former U.S. President Bill Clinton, right, cheers during the speech of former New York City Mayor Michael Bloomberg.

Kaine comes out to the stage on Wednesday.

Kaine comes out to the stage on Wednesday.

During his speech, Kaine said: "Hillary Clinton and I are compañeros del alma. We share this belief: Do all the good you can. And serve one another. Pretty simple. That's what I'm about. That's what you're about. That's what Bernie Sanders is about. That's what Joe Biden is about. That's what Barack and Michelle Obama are about. And that's what Hillary Clinton is about."

During his speech, Kaine said: "Hillary Clinton and I are compañeros del alma. We share this belief: Do all the good you can. And serve one another. Pretty simple. That's what I'm about. That's what you're about. That's what Bernie Sanders is about. That's what Joe Biden is about. That's what Barack and Michelle Obama are about. And that's what Hillary Clinton is about."

Clinton's running mate, Tim Kaine, waves to the crowd along with his wife, Anne Holton, after giving a speech on Wednesday.

Clinton's running mate, Tim Kaine, waves to the crowd along with his wife, Anne Holton, after giving a speech on Wednesday.

Obama said Clinton is more ready than he was to become President. "For four years, I had a front-row seat to her intelligence, her judgment and her discipline," Obama said, referring to her stint as secretary of state.

Obama said Clinton is more ready than he was to become President. "For four years, I had a front-row seat to her intelligence, her judgment and her discipline," Obama said, referring to her stint as secretary of state.

Obama told the crowd at the Wells Fargo Center that he is "more optimistic about the future of America than ever before." He contrasted it with the "pessimistic vision" of America he heard during the Republican convention last week. "There were no serious solutions to pressing problems -- just the fanning of resentment, and blame, and anger, and hate," he said.

Obama told the crowd at the Wells Fargo Center that he is "more optimistic about the future of America than ever before." He contrasted it with the "pessimistic vision" of America he heard during the Republican convention last week. "There were no serious solutions to pressing problems -- just the fanning of resentment, and blame, and anger, and hate," he said.

"This year, in this election, I'm asking you to join me -- to reject cynicism, reject fear, to summon what's best in us; to elect Hillary Clinton as the next President of the United States, and show the world we still believe in the promise of this great nation," Obama said.

"This year, in this election, I'm asking you to join me -- to reject cynicism, reject fear, to summon what's best in us; to elect Hillary Clinton as the next President of the United States, and show the world we still believe in the promise of this great nation," Obama said.

Clinton points to Obama as she walks on stage after his speech.

Clinton points to Obama as she walks on stage after his speech.

Clinton and U.S. President Barack Obama wave to the crowd Wednesday after Obama gave a speech.

Clinton and U.S. President Barack Obama wave to the crowd Wednesday after Obama gave a speech.

House Minority Leader Nancy Pelosi speaks to the crowd at the Wells Fargo Center.

House Minority Leader Nancy Pelosi speaks to the crowd at the Wells Fargo Center.

Khizr Khan holds his personal copy of the U.S. Constitution as he speaks Thursday. His son, Humayun S. M. Khan, was one of the 14 American Muslims who have died serving their country since 9/11. In his remarks, Khan criticized the Republican nominee: "If it was up to Donald Trump, (my son) never would have been in America. ... Donald Trump, you are asking Americans to trust you with our future. Let me ask you: Have you even read the U.S. Constitution? I will gladly lend you my copy."

Khizr Khan holds his personal copy of the U.S. Constitution as he speaks Thursday. His son, Humayun S. M. Khan, was one of the 14 American Muslims who have died serving their country since 9/11. In his remarks, Khan criticized the Republican nominee: "If it was up to Donald Trump, (my son) never would have been in America. ... Donald Trump, you are asking Americans to trust you with our future. Let me ask you: Have you even read the U.S. Constitution? I will gladly lend you my copy."

Chelsea Clinton said her mother is a "listener and a doer, a woman driven by compassion, by faith, by kindness, a fierce sense of justice, and a heart full of love."

Chelsea Clinton said her mother is a "listener and a doer, a woman driven by compassion, by faith, by kindness, a fierce sense of justice, and a heart full of love."

Bill Clinton becomes emotional Thursday as he listens to Chelsea introduce her mother.

Bill Clinton becomes emotional Thursday as he listens to Chelsea introduce her mother.

Clinton is the first woman in U.S. history to lead the presidential ticket of a major political party. "It's true," she said in her speech, "I sweat the details of policy -- whether we're talking about the exact level of lead in the drinking water in Flint, Michigan; the number of mental health facilities in Iowa; or the cost of your prescription drugs. ... Because it's not just a detail if it's your kid, if it's your family. It's a big deal. And it should be a big deal to your President."

Clinton is the first woman in U.S. history to lead the presidential ticket of a major political party. "It's true," she said in her speech, "I sweat the details of policy -- whether we're talking about the exact level of lead in the drinking water in Flint, Michigan; the number of mental health facilities in Iowa; or the cost of your prescription drugs. ... Because it's not just a detail if it's your kid, if it's your family. It's a big deal. And it should be a big deal to your President."

Clinton's husband, former U.S. President Bill Clinton, applauds along with their daughter, Chelsea.

Clinton's husband, former U.S. President Bill Clinton, applauds along with their daughter, Chelsea.

During her speech, Clinton ripped into Republican nominee Donald Trump for his convention pitch "I alone can fix it." She said: "He's forgetting every last one of us. Americans don't say: 'I alone can fix it.' We say: 'We'll fix it together.' "

During her speech, Clinton ripped into Republican nominee Donald Trump for his convention pitch "I alone can fix it." She said: "He's forgetting every last one of us. Americans don't say: 'I alone can fix it.' We say: 'We'll fix it together.' "

Balloons fall from the ceiling of the Wells Fargo Center after Clinton's speech.

Balloons fall from the ceiling of the Wells Fargo Center after Clinton's speech.

Clinton walks on stage with her running mate, U.S. Sen. Tim Kaine.

Clinton walks on stage with her running mate, U.S. Sen. Tim Kaine.

Hillary Clinton, the Democratic Party's presidential nominee, takes the stage before giving a speech Thursday at the Democratic National Convention in Philadelphia.

Hillary Clinton, the Democratic Party's presidential nominee, takes the stage before giving a speech Thursday at the Democratic National Convention in Philadelphia.

Obama was in Philadelphia at the Democratic National Convention 12 years to the day after he shook politics with a convention speech in Boston that encouraged Americans to look at the common threads that unite them. He offered a similarly empowering vision of the nation Wednesday, saying America doesn't need a "self declared savior" like Donald Trump to fix it.

Undaunted by the experience of a presidency that unfolded in a time of crisis and deep ideological divides, he renewed his faith in the idea of a unified nation. The speech crystalized the two visions of America emerging this election season, following last week's Republican National Convention in which Trump blasted Obama for leaving the country divided and plagued by crime.

"The America I know is full of courage, and optimism, and ingenuity," Obama said. "The America I know is decent and generous. Sure, we have real anxieties -- about paying the bills, protecting our kids, caring for a sick parent. We get frustrated with political gridlock, worry about racial divisions; are shocked and saddened by the madness of Orlando or Nice."

He went on: "But as I've traveled this country, through all fifty states; as I've rejoiced with you and mourned with you, what I've also seen, more than anything, is what is right with America."

Obama then made an impassioned case for Clinton, saying no man or woman had ever been as prepared to be president.

"Nothing truly prepares you for the demands of the Oval Office," Obama said. "But Hillary's been in the room; she's been part of those decisions."

He acknowledged Clinton had made mistakes, but compared her to Teddy Roosevelt's valiant striver who errs, but also knows great triumphs.

"Hillary Clinton is that woman in the arena," Obama said.

He also made an appeal to Bernie Sanders supporters who are still cool on Clinton.

"You've got to get in the arena with her, because democracy isn't a spectator sport," he said.

Obama hugs Clinton during the third night of the Democratic National Convention in Philadelphia, Pennsylvania.

Throughout the night, speaker after speaker leveled heated criticism of Trump aimed at undermining his image as a tough guy who understands Americans. Vice President Joe Biden painted Trump as completely unqualified for the presidency.

"He is trying to tell us he cares about the middle class. Give me a break. That's a bunch of malarky," Biden said. "This guy doesn't have a clue about the Middle Class. Not a clue."

The crowd roared with approval, chanting "not a clue."

Biden said Trump was unable to handle the complexities of a dangerous world.

"No major party nominee in the history of this nation has ever known less or has been less prepared to deal with our national security," he said.

Biden used his address on the third night of the Democratic National Convention to appeal to middle-class voters, a group Clinton is under pressure to win over. Leveraging his blue-collar bona fides, he argued Clinton is intimately familiar with the economic disenfranchisement that helped power Trump's rise.

On Thursday, Trump told a crowd at a rally in Davenport, Iowa, the Democrats are acting "like everything is wonderful."

"I watched last night, and it was like all beautiful roses," he said.

'Hillary gets it'

"Everybody knows she is smart," Biden said. "Everybody knows she is tough. But I know what she is passionate about. I know Hillary. Hillary understands. Hillary gets it."

Former New York Mayor Michael Bloomberg, meanwhile, said he was not a Democrat or a Republican but appeared at the convention to demolish his fellow billionaire's reputation in business.

"I believe we need a president who is a problem-solver, not a bomb-thrower," said Bloomberg.

He quipped that unlike Trump, he didn't start his business empire with a "million dollar check from my father."

"Trump has left behind a well-documented record of bankruptcies, thousands of lawsuits, angry shareholders and contractors who feel cheated, and disillusioned customers who feel ripped off," Bloomberg said. "Trump says he wants to run the nation like he's run his business. God help us!"

"I am a New Yorker, and I know a con when I see one."

He went on: "The bottom line is: Trump is a risky, reckless, and radical choice. And we can't afford to make that choice!"

The night of the DNC also offered a big opportunity for Tim Kaine, Clinton's vice presidential pick, who introduced himself to an audience unfamiliar with his years as a governor and senator in Virginia.

He affected an impression of Trump and used the billionaire's verbal tick "Believe Me" to ridicule him as a "slick talking, empty promising, self promoting, one man wrecking crew."

Noting that his son, Nat, deployed with the US Marines this week, Kaine quickly slammed Trump for raising the possibility that his administration wouldn't always defend NATO allies.

Kaine said his son would "protect and defend the very NATO allies that Donald Trump now says he wants to abandon."

He made a case that Americans should trust Clinton.

"I trust Hillary Clinton with our son's life," Kaine said. "You know who I don't trust? Donald Trump."

"You cannot believe one word that comes out of Donald Trump's mouth. Not one word," Kaine said, slamming the GOP nominee as a "slick talking, empty promising, self promoting, one man wrecking crew."

Security theme

The night's underlying theme was security — national security, economic security and safety from gun crime.

Leon Panetta, the former CIA director and secretary of defense, lashed out at Trump over his apparent call on Russian intelligence agencies to help find emails that Hillary Clinton deleted from her private server.

"Today, Donald Trump today once again took Russia's side. He asked the Russians to interfere in American politics. Think about that for a moment. Donald Trump, who wants to be president of the United States, is asking one of our adversaries to engage in hacking or intelligence efforts against the United States of America to affect an election," Panetta said.

"As someone who was responsible for protecting our nation from cyberattacks, it's inconceivable to me that any presidential candidate would be that irresponsible," he said. "Donald Trump cannot become our commander-in-chief."

During his remarks, some Bernie Sanders supporters began to chant "No More War!" but were drowned out by counter chants of "USA, USA."

Soon after Panetta spoke, the Trump campaign released a statement criticizing the former defense secretary's stance.

"It is alarming that Leon Panetta would, through his silence, excuse Hillary Clinton's enablement of foreign espionage with her illegal email scheme and her corrupt decision to then destroy those emails and dissemble her 'private' server to hide her crimes from the public and authorities," Trump senior policy adviser Stephen Miller said. He also argued that it was Clinton who is endangering national security with her policies in the Middle East and North Africa.

The FBI recommended not to bring criminal charges against Clinton earlier this month related to her private email server.

But the night will likely be most remembered for the power of Obama's rhetoric.

He appeared deeply emotional as he began to take his leave of the nation he has led.

"For all the tough lessons I've had to learn; for all the places I've fallen short; I've told Hillary, and I'll tell you what's picked me back up, every single time," Obama said. "It's been you. The American people."