President Donald Trump honored the 2,977 people who lost their lives in the 9/11 terrorist attack during a somber 25th anniversary tribute at the Pentagon on Friday.

In a speech that recounted the personal stories of individuals who lost their lives in the hijacked plane attacks in 2001, the president pledged to “never ever forget.”

“A generation has passed since the terror attacks of Sept. 11, 2001, yet time has not dimmed the honor of that day when our country came face to face with true evil,” he said.

The president recalled a trio of 11-year-olds headed for a field trip and a family bound for an international adventure on American Airlines Flight 77, which had just taken off from Washington Dulles Airport en route to Los Angeles when hijackers crashed it into the Pentagon, killing 59 passengers and crew on the plane and 184 in the Defense Department’s headquarters.

He shared the story of 35-year-old Patrick Danahy, who was working on the 90th floor of the World Trade Center’s South Tower when he called to tell his pregnant wife he was safe after the North Tower had been struck. He died after the South Tower was struck by United Airlines Flight 175.

Trump also recounted one of the most famous stories from that day, when Todd Beamer, a passenger on United Airlines Flight 93, helped lead a revolt against the hijackers and said “let’s roll” before passengers stormed the cockpit and brought down the plane in a field near Shanksville, Pennsylvania, to stop it from hitting its intended target.

“Free people must never avert their eyes from such hideous cruelty,” Trump said. “We cannot forget that moment of immense and horrible evil that took place in this world, bent on the destruction of all that is good. But this morning, we also remember how Americans responded to that wickedness.”

In a nod to American unity, Trump recalled the immediate aftermath of the attack, when “we were all New Yorkers that day. Every one of us. But we were also all Americans. We were all family. We were all patriots.”

Trump was speaking from a stage where the largest American flag in the military’s collection was mounted. It was the same flag three firefighters hung near the holes in the Pentagon building on Sept. 12, 2001, as a symbol of American defiance.

In several veiled references to the Iran war, Trump said the U.S. continues to honor the lives lost on 9/11 by fighting.

“In the generation since 9/11, American sons and daughters have traveled to the darkest corners of the earth and done battle with a shadowy enemy so that our children might once again know carefree days and cloudless skies,” he said.

In an 18-minute speech, he praised 9/11’s first responders and law enforcement, as well as U.S. service members who served in the “war on terror” — the global campaign President George W. Bush declared after 9/11 to defeat terrorist groups, which resulted in the U.S. wars in Afghanistan and Iraq.

On Friday, Trump said service members continue the fight today, “working right now to ensure the world’s No. 1 sponsor of terror — the Islamic Republic of Iran — will never, ever have a nuclear weapon.”

Recognizing that the country has forever been changed by the worst terrorist attack on U.S. soil, Trump said the American spirit hasn’t only endured but prevailed in the 25 years since 9/11.

“On days like 9/11, we learn what a country is truly made of. … Americans are made of a goodness and spirit that can transcend any earthly force,” he said.

Trump pledged the United States will be “a nation whose heroes are not fanatics for an abstract cause … but the kind who race into buildings and give their lives on a Tuesday morning for strangers they’ve never met.”