President Joe Biden commemorated the 21st anniversary of the 9/11 terror attacks at a remembrance event Sunday at the Pentagon, delivering heartfelt remarks that honoured those killed there.

“I know for all those of you who lost someone, 21 years is both a lifetime and no time at all,” Biden said at the National 9/11 Pentagon Memorial in Arlington, Virginia.

“It’s good to remember. These memories help us heal, but they can also open up the hurt and take us back to that moment when the grief was so raw.”

The President talked about a message sent to the American people on September 11, 2001, from Queen Elizabeth II of the United Kingdom, who died Thursday, recalling that she “pointedly reminded us, quote, ‘Grief is the price we pay for love.'”

As he has in several recent speeches, Biden talked on Sunday about securing American democracy. But he softened his rhetoric and avoided some of the more politically charged statements he’s made in the lead up to the midterms.

“It’s not enough to stand up for democracy once a year or every now and then. It’s something we have to do every single day,” the President said. “So this is a day not only to remember, but a day of renewal and resolve for each and every American and our devotion to this country.”

Nearly 3,000 people died in the 9/11 attacks, which were orchestrated by al Qaeda leader Osama bin Laden. Hijacked airliners crashed into the World Trade Center in New York City, the Pentagon in Arlington, Virginia, and a field near Shanksville, Pennsylvania.

Biden in his speech also highlighted the killing of al Qaeda leader Ayman al-Zawahiri in a drone strike earlier this year, saying the US “will not rest, we’ll never forget, we will never give up”.

“And now Zawahiri can never again threaten the American people,” the President said.

Before the speech, Biden participated in a wreath-laying ceremony at the Pentagon, pausing briefly in front of a ceremonial wreath to touch it and then putting his hand over his heart. He was joined at the event by Chairman of the Joint Chiefs of Staff Mark Milley and Defense Secretary, Lloyd Austin. (CNN)