President Joe Biden said "you can't love your country only when you win" in his first speech since Vice President Kamala Harris' loss to former President Donald Trump in the presidential race.

"You can't love your neighbor only when you agree," Biden said in an address to the nation from the White House Rose Garden on Thursday.

Biden said he's directed his administration to work with Trump's team for a peaceful transition of power.

"Something I hope we can do, no matter who you voted for, is see each other not as adversaries, but as fellow Americans. Bring down the temperature," Biden said.

He also stressed the integrity of the election, calling it honest, fair and transparent.

"The will of the people always prevails," he said.

Biden praised his vice president for running "an inspiring campaign."

"She has great character, true character. She gave her whole heart and effort, and she and her entire team should be proud of the campaign they ran," he said.

Biden also defended some of his actions in office, saying, "We're going to see over a trillion dollars' worth of infrastructure work done, changing people's lives in rural communities and communities that are in real difficulty, because it takes time to get it done."

"We're leaving behind the strongest economy in the world," Biden added.

"I know people are still hurting," he said, but added, "Together, we've changed America for the better."

"Setbacks are unavoidable, but giving up is unforgivable," Biden said in his closing message to Americans.

"We're going to be OK, but we need to stay engaged. We need to keep going," he added. "And above all, we need to keep the faith."

Biden said in a statement on Wednesday that adding Harris to his 2020 Democratic ticket was the first and "best decision" he made in that campaign.

"Her story represents the best of America's story," Biden said, adding, "I have no doubt she'll continue writing that story."

His statement made no mention of Trump, the former Republican president and now president-elect, who will bookend Biden's sole term in office.

Biden and Harris have both spoken to Trump on the phone to congratulate him.

Harris in a speech on Wednesday conceded the race to Trump.

Harris stressed, "While I concede this election, I do not concede the fight that fueled this campaign."

"This is not a time to throw up our hands, this is a time to roll up our sleeves. This is a time to organize, to mobilize and to stay engaged for the sake of freedom and justice and the future that we all know we can build together," she said.

Trump won the swing states of North Carolina, Pennsylvania, Georgia, Wisconsin and Michigan. ABC News has not projected winners for the final two swing states, Nevada and Arizona.

Republicans also took control of the Senate. Results for the House of Representatives are not yet clear.

ABC News' Michelle Stoddart contributed to this report.