(CNN) Looking out into an African-American congregation this weekend at the New Mount Olive Baptist Church in Fort Lauderdale, Hillary Clinton preached about God's commandment to love each other, the resilience of her late mother, the need to tackle systemic racism and help parents left grieving by violence.

In the pews, the audience nodded along, showing their approval by muttering "Amen" and raising their hands up in the air. But it wasn't until Clinton delivered this line that the worshippers rose to their feet.

"I am going to defend President Obama's legacy," Clinton said. "Especially the Affordable Care Act."

It was the third time in October that Clinton spent her Sunday morning at a black church in the final stretch of the 2016 campaign, hoping to capture President Barack Obama's powerful coalition, which will be key to whether she can win states like North Carolina and Florida -- and capture the White House.

For Obama, whose final mission as president is the election of a Democratic successor and the preservation of his eight-year legacy, next Tuesday will serve as a testament to whether he was able to help his one-time opponent close the deal in a historic election.

Obama laid out a strong pitch Wednesday to black voters with radio host Tom Joyner, imagining what it would be like to prepare for a transition to a Donald Trump presidency and calling on African-Americans to come out and vote to make sure his legacy is not reversed.

Obamacare, Medicaid, support for historically black colleges and universities, the work done on civil rights, voting rights and criminal justice reform -- even the first lady's vegetable garden -- would be at risk under Trump, the President said in the interview taped Tuesday and aired Wednesday morning.

And Obama called out his supporters who aren't jumping in to help out Clinton.

"I need you and everybody who is listening to make it their sole focus over the next seven days that every single person is out there voting. And I'm gonna be honest with you right now, because we track, we've got early voting, we've got all kinds of metrics to see what's going on and right now, the Latino vote is up, overall vote is up, but the African-American vote right now is not as solid as it needs to be," Obama said.

"And I know that there are a lot of people in barbershops and beauty salons, you know, in the neighborhoods who are saying to themselves 'We love Barack, we love -- we especially love Michelle -- and so, you know, it was exciting and now we're not excited as much,'" he added. "You know what? I need everybody to understand that everything we've done is dependent on me being able to pass the baton to somebody who believes in same things I believe in."

Obama heads into the final months of his presidency with the highest approval rating of his second term. A CNN/ORC poll last month showed 55% of Americans have a favorable view of the president , and his approval rating has stayed at 50% or higher in that survey since February.

But those numbers won't make Obama feel good next year if he's watching President Trump and Republicans dismantle eight years of hard work.

In recent months, Obama has embraced, and at times even appeared to relish, using his powerful bully pulpit to give weight to Clinton's main attack line against her opponent -- that Trump is simply unqualified and unfit to be president.

Since Clinton clinched the Democratic nomination this summer, the president has campaigned twice in North Carolina as well as Florida, and stumped in Pennsylvania, Ohio, and Nevada. Wednesday, he'll appear at the University of North Carolina at Chapel Hill, and will be in Florida later in the week.

"There's not a battleground state that he's not effective in," one senior Clinton adviser said. The adviser did not rule out the possibility of a joint Clinton-Obama event in the final days of the election.

And Democrats believe there is no surrogate more capable of helping bring home two critical demographic groups for Clinton: African-Americans and young people.

At the same time, Obama has his limitations, especially when it comes to Clinton's recent troubles with FBI Director James Comey.

Obama has steered clear of criticizing the agency, and the recently revived email investigation -- where Clinton needs the most validation -- is an area where the president is unable to offer her a full-throated defense.

Obama conducted 13 interviews on black radio shows in the months of September and October, five of which were broadcast during drive time. Of the local interviews, four were hosts in Florida, where African-American turnout for in-person early voting has been lower than expectations.

But Clinton aides insist that Obama's outreach is working there, where their analysis says 500,000 African Americans have already cast their ballots in Florida through both in-person voting and through mail-in ballots. That number is up 74% compared to the same time in 2012, aides said, and represents a 30% higher rate of mail-in ballot requests from African-Americans than in 2012.

In North Carolina, the Clinton campaign is tracking higher than expected in-person early voting among African-Americans. Turnout in Mecklenberg, Orange, Wake and Durham counties, where one in three people are black, is up 17% on average, according to the campaign's data.

And as a part of his outreach to young voters -- a group that Clinton struggled to excite during the Democratic primaries -- Obama has lit up social media and late night TV. He has given interviews to wide-reach platforms like Snapchat and YouTube, and sat down with popular comedians like Stephen Colbert and Jimmy Kimmel.

In an interview with comedian Samantha Bee this week, Obama called on young people to vote, pointing out that his daughter, Malia, voted for the first time in this election.

"The pride that she took, I think, in casting her ballot, is a pride that I think a lot of young people feel, but, you got to talk to them about the things that they care about," he said.

Clinton keeping Obama close

Clinton's embrace of Obama was prominent during the Democratic primaries. During the grueling 14-month race against Vermont Sen. Bernie Sanders, Clinton touted herself as the rightful heir to the president's legacy and painted Sanders as someone who both lacked a full appreciation for and wanted to re-write Obama's accomplishments.

This was an especially important selling point for Clinton with black voters, a bloc that proved to be critical to Clinton's ability to overcome Sanders' unexpectedly strong challenge from the left.

At a February debate in South Carolina, Clinton slammed Sanders for calling Obama "weak" and a "disappointment."

"The kind of criticism that we heard from Sen. Sanders about our president, I expect from Republicans," Clinton said. "I do not expect (it) from someone running for the Democratic nomination to succeed President Obama."

"Madam Secretary, that is a low blow," Sanders shot back, clearly understanding the power of the attack.

In addition to using Obama as a validator (she has often reminded Democrats that the president thought highly enough of her to ask her to be his secretary of state), Clinton has also cast herself as the true defender of Obama's policies on issues ranging from Obamacare to gun control.

"It is time to pick a side," Clinton said in an ad released in January. "Either we stand with the gun lobby or we join the President and stand up to them I am with him."

Campaigning for Clinton in Columbus, Ohio, on Tuesday, Obama implored men who are not supporting Clinton to think hard about their opposition, and whether it has to do with the nominee's gender.

"I know that my wife is not just my equal but my superior," Obama said. "When a guy's ambitious out in the public arena and working hard, well, that's OK. But when a woman does it, suddenly we're like, why's she doing that?"

"I want you to think about that," Obama continued, adding about Clinton: "She is so much better qualified than the other guy."