“I join you on this solemn day to renew our sacred vow, ‘never forget,’” Mr Biden said.
“Hundreds of thousands of brave Americans deployed to Afghanistan to make sure the United States would not be attacked again, who served in Iraq, like many of you probably did, in war zones,” he said. He noted how recently, the US Intelligence Community said that the threat from al-Qaeda in Afghanistan and Pakistan reached an all-time low.
“The resolve of the American people has proved we never bow, we never bend, we never yield,” he said. Mr Biden also noted how he ordered the end of US military operations in Afghanistan, which led to the Afghan government falling to the Taliban.
“Our longest war is over, but the current commitment preventing another attack on the United States in our people and our allies will never never rest,” he said.
Mr Biden recalled standing at Ground Zero in Manhattan after terrorists attacked the World Trade Center, killing almost 3,000 people in 2001.
“I remember standing there the next day and looking at the building. I felt like I was looking through the gates of hell, it looked so devastating” he said. Mr Biden was at the time a senator from Delaware who was the top Democrat on the Senate Foreign Relations Committee.
The president also called for national unity amid a rising tide of political extremism.
“It's more important than ever that we come together around the principle of American democracy, regardless of our political backgrounds,” he said. “We must not succumb to the poisonous politics of difference and division must never allow ourselves to be pulled apart, by petty manufactured grievances.”
Mr Biden visited the military base after attending the G20 summit in New Delhi and visiting Vietnam. Some in conservative media, including the Rupert Murdoch-owned Fox News, criticised Mr Biden for not visiting New York City, the Pentagon or Shanksville, Pennsylvania – the sites of the terror attacks on September 11, 2001.
But Vice President Kamala Harris joined elected officials in New York City to commemorate the 9/11 terrorist attacks in the president’s stead while First Lady Jill Biden laid a wreath at the National 9/11 Pentagon Memorial in Arlington, Virginia. Similarly, Second Gentleman Doug Emhoff visited Shanksville, Pennsylvania, the site of the Flight 93 crash of a plane meant for Washington, DC the same day as the attacks in New York and the Pentagon.
Mr Biden hailed the generosity of Alaskans during the terrorist attacks in his speech, as well as across the country.
“Alaskan communities opened their doors to stranded passengers,” he said. “American flags sold out in every store, were placed in front of seemingly every home. We know that on this day every American's heart was wounded. Yet, every big city, small town, suburb or rural town, tribal community, American hands went up, ready to help where they could.”
During his time as a senator, Mr Biden supported the war in Afghanistan, though as vice president he came to express reservations. As president, he sought to end US military involvement in Afghanistan but received widespread criticism and tumbling approval ratings as many Americans and allies struggled to escape amid the collapse of the Afghan government.
Toward the end of his speech, Mr Biden called for the nation to not forget the day and aftermath of the attacks.
“Let us remember who we are as a nation,” he said. “We never forget. We're never afraid. We endure, we overcome. We are the United States of America. And there is nothing, literally, historically, nothing has been beyond our capacity when we set our mind to it together.”