Obama at Pentagon: Diversity One of America's 'Greatest Strengths' to Defeat Terrorists

ARLINGTON, Va. -- President Obama said the U.S. has delivered "devastating blows" to al-Qaeda and stressed that America needs to lean on "our patchwork heritage" to resist terrorists' attempts make Americans turn on each other.

Delivering remarks at the Pentagon to mark the 15th anniversary of the 9/11 attacks, Obama paid tribute to "the nearly 3,000 beautiful lives taken from us so cruelly -- including 184 men, women and children here, the youngest just 3 years old."

"We honor the courage of those who put themselves in harm’s way to save people they never knew. We come together in prayer and in gratitude for the strength that has fortified us across these 15 years. And we renew the love and the faith that binds us together as one American family," he said.

"...The question before us, as always, is: How do we preserve the legacy of those we lost? How do we live up to their example? And how do we keep their spirit alive in our own hearts?"

Obama said "we have seen the answer in a generation of Americans -- our men and women in uniform, diplomats, intelligence, homeland security and law enforcement professionals -- all who have stepped forward to serve and who have risked and given their lives to help keep us safe."

"Thanks to their extraordinary service, we’ve dealt devastating blows to al-Qaeda. We've delivered justice to Osama bin Laden. We’ve strengthened our homeland security. We've prevented attacks. We've saved lives. We resolve to continue doing everything in our power to protect this country that we love," he said.

The president emphasized a need to "stay true to the spirit of this day by defending not only our country, but also our ideals."

"Fifteen years into this fight, the threat has evolved. With our stronger defenses, terrorists often attempt attacks on a smaller, but still deadly, scale. Hateful ideologies urge people in their own country to commit unspeakable violence. We’ve mourned the loss of innocents from Boston to San Bernardino to Orlando," he continued.

"Groups like al-Qaeda, like ISIL, know that we will never be able -- they will never be able to defeat a nation as great and as strong as America. So, instead, they've tried to terrorize in the hopes that they can stoke enough fear that we turn on each other and that we change who we are or how we live. And that's why it is so important today that we reaffirm our character as a nation -- a people drawn from every corner of the world, every color, every religion, every background -- bound by a creed as old as our founding, e pluribus unum. Out of many, we are one. For we know that our diversity -- our patchwork heritage -- is not a weakness; it is still, and always will be, one of our greatest strengths. This is the America that was attacked that September morning. This is the America that we must remain true to."