First lady Melania Trump on Monday afternoon tweeted a nearly seven-minute long farewell video looking back on her time in the White House.

She said serving as first lady has been "the greatest honor of my life" and reflected on her "Be Best" initiative, work combatting the opioid crisis and more.

"No words can express the depth of my gratitude for the privilege of having served as your first lady," she said. "To all the people of this country, you will be in my heart forever. Thank you. God bless you, and God bless the United States of America."

Her video comes just under two weeks after Trump supporters violently sieged the Capitol building and just days before Biden's inauguration.

In her farewell message to Americans, the first lady said, "Be passionate in everything you do. But always remember that violence is never the answer and will never be justified."

-ABC News' Elizabeth Thomas

To mark the holiday celebrating the legacy of Martin Luther King Jr., Vice President-elect Kamala Harris participated in a service activity focused on food insecurity in the nation's capital on Monday.

She packed bags of food alongside her husband Doug Emhoff at Martha's Table, an initiative focused on increasing access to healthy meals in Southeast Washington.

"I think it's so important to remember that Dr. King was killed in large part, I believe, because he was on the verge of bringing together the Civil Rights movement around racial justice with the fight for economic justice," Harris said. "And when we look at where we are as a country today, when we look at recent events, we know that the fight that Dr. King was engaged in is still a fight in America, which is to recognize the connection and to recognize our collective responsibility to address these injustices."

She also spoke about the tasks ahead as she prepares to become vice president, saying she and Biden are going into Wednesday "ready to do the work."

"And we've got a lot of work to do," she added, referencing plans for vaccinations and economic recovery.

When asked if their proposed one-time $1,400 stimulus check was enough for Americans, Harris called it a "start."

"There's a lot more to do, which is why there are so many other components to our relief package and the work that we are committed to doing going forward," she said.

Finally, Harris spoke about how she's feeling ahead of her historic swearing-in, which has faced unprecedented security threats.

"I am very much looking forward to be sworn in as the next vice president of the United States, and I will walk there, to that moment, proudly with my head up and my shoulders back," Harris said.

-ABC News' Averi Harper

Country singer Garth Brooks will be joining the Biden inauguration celebration on Wednesday and perform during Biden's swearing-in ceremony at the Capitol, the Presidential Inaugural Committee announced Monday.

Brooks has performed for every president since Jimmy Carter, with the exception of Ronald Reagan.

He will join previously announced performers Lady Gaga and Jennifer Lopez. During the virtual press conference, Brooks stressed that his decision to perform at the Capitol was not a political one, but one focused on unity -- a message that the Biden administration has pushed as they get ready to enter office.

"I am a civilian of the greatest country on the planet," Brooks said. "So our job is to work as hard as we can for all of us to have a better future than before."

Brooks even quipped that he "might be the only Republican" at the inauguration, but said he wanted to move past the divided nature of the country.

-ABC News' Molly Nagle

Alex Padilla officially resigned as California's secretary of state on Monday in order to assume Vice President-elect Kamala Harris' Senate seat.

Harris resigned her Senate seat earlier Monday.

Padilla called it a "true honor and privilege" to serve as California's secretary of state in a statement reflecting on the agency's progress over the past six years.

"As I prepare to enter the United States Senate, I will carry on the mission of building a more inclusive democracy and economy for all," Padilla added.

James Schwab, the former chief deputy secretary of state in California, will serve as interim secretary of state.

-ABC News' Kendall Karson

In his appearance on ABC's "This Week" Sunday, Biden’s nominee for Surgeon General Vivek Murthy said that when it comes to meeting the goal for 100 million vaccines in the first 100 days of the president's administration, there are things that could go right or wrong.

"I think President Biden fully understands there's a larger goal here, as we all do, which is that we've got to vaccinate as many Americans as possible. And that's going to take a lot of work, work dispelling this disinformation, working on the supply, increasing distribution channels," he told ABC News Chief Anchor George Stephanopoulos. "And that's some of what the vaccine plan that he announced over the last week is intended to -- to achieve."

Stephanopoulos pressed Murthy on whether there are ways to increase the supply and equitably distribute the vaccines.

"It appears, at least in these first vaccines that have gone out, they've been going largely to wealthier areas of the country, largely to whiter areas of the country," Stephanopoulos said.

"Well, it's the right question, George, because success has to be gauged not just by the number of vaccines we deliver but also by how fairly we deliver those vaccines -- how equitably we deliver them," he said in response. "What we've got to do here is not just, again, increase supply, which we can do using the Defense Production Act ... but we've also got to set up the kind of distribution channels, like mobile units, like strategically placed community vaccination centers, that can reach people who traditionally are hard to reach and don't have access to health care."

He added, "We have got to track our progress. We have got to make sure that we have data on where the vaccine is being administered, so that we can ensure that it, in fact, is being distributed equitably."