Hillary Clinton tells PEOPLE: "I will never stop believing in this country and our collective future"

Hillary Clinton, After Massive Marches Protesting President Trump's Agenda, Tells PEOPLE: 'We Have to Keep Up the Momentum'

Hillary Clinton has a message for the millions of “awe-inspiring” women and men who marched in Washington, D.C. and in cities around the world on Saturday to protest the inauguration of President Donald Trump — keep up the good fight.

The 2016 Democratic presidential nominee, who notably attended her former opponent’s inauguration on Friday, tells PEOPLE in this week’s issue that she did so “to honor democracy and its enduring values.”

Get push notifications with news, features and more.

“On Saturday, we watched women and men across this country and the globe stand up, speak out, and peacefully march for those values with one voice,” she continued. “It was awe-inspiring. We have to keep up the momentum.”

Image zoom Joe Raedle/Getty Images

RELATED VIDEO: Watch: Natasha Stoynoff Breaks Silence, Accuses Donald Trump of Sexual Attack

Clinton did not participate in the Women’s March on Washington but voiced her support on Twitter during the peaceful protests and in the days following.

She also echoed her sentiments about continuing to fight Trump’s agenda in a tweet to former Philadelphia Mayor Michael Nutter on Sunday: