His friend’s eldest son, Davis Jr., had worked for just six days in a new job on the 104th floor of the World Trade Center’s south tower. At 8:46 a.m. on that fateful Tuesday morning, a plane hit the north tower. Seventeen minutes later, a plane hit the south tower.

“They went straight to Ground Zero to search for a son,” Biden said. “They searched deep, until the last ending hope.”

The year before, his friend’s family had lost their youngest son, a 15-year-old who died in a boating accident. Despite the dual tragedies, Biden’s friend reminded him of what was most important.

“I was on my way to speak to the students at the University of Delaware about what to make of the new world we were in,” Biden said. “He told me to tell people, quote, “Don’t be afraid. Tell them, ‘Don’t be afraid.’”

Biden called it “extraordinary and yet the most ordinary of American things: to know life can be unfair and uncertain—a cruel twist, accident or a deliberate act of evil—but even in darkness, to still be the light.”

America and the world both commemorate the families of the 2,977 people from over 90 nations killed during the September 11, 2001 attacks in New York City; Arlington, Virginia; and Shanksville, Pennsylvania, Biden said. Biden also commemorated the 1,000 people who were injured as well as their families.

Biden also praised those who helped “rescue, recover and rebuild” immediately after the attack. He honored first-responders, medical workers, construction workers, faith leaders, military service members, veterans and others “who risked and gave their lives” to help during “the minutes, hours, months and years after” the attack.

“We saw heroism everywhere in places expected and unexpected,” he added. “We also saw something all too rare, a true sense of national unity.”

The president acknowledged the hardship of those who had to continue life without their loved ones who perished in the attack. This includes young children entering their 20s who grew up without a parent, spouses who had to endure being widowed as well as family and friends who’ve had to celebrate birthdays and other milestones “with a hole in their heart,” he said.

Biden then pledged to always hunt down anti-American terrorists. He said that in the days following the attack, the nation experienced a rare sense of national unity towards this goal and towards re-emerging stronger than before.

“Unity doesn’t mean we have to believe the same thing,” he explained. “We must have a fundamental respect and faith in each other, and in this nation.”

He said that the U.S. remains unique in world history for its foundation upon the belief that all humans are equal and should be treated so throughout their lives. By continuing to rebuild from the attacks—by acting with honor and courage rather than reactionary fear, Biden said—the U.S. can provide a powerful example of dedication to the faith and wonder of life.

Newsweek contacted the White House for comment.