"Your generation, a young generation, has come of age in a world with fewer walls. You've been educated in an era of instant information. You've been tempered by some very difficult times around the globe," Obama told a young town-hall audience.
"Here, in Northern Ireland, this generation has known even more rapid change than many young people have seen around the world. And while you have unique challenges of your own, you also have unique reasons to be hopeful," Obama said before attending the Group of Eight summit.
"For you are the first generation in this land to inherit more than just the hardened attitudes and the bitter prejudices of the past. You're an inheritor of a just and hard-earned peace."
If today's youth maintain their "courageous path toward a permanent peace, and all the social and economic benefits that have come with it," not only would Northern Ireland benefit, but also the entire island, the United Kingdom, Europe and the world, the president said.
Fifteen years have passed since the 1998 Good Friday Agreement ended The Troubles in Northern Ireland, but work for lasting peace never ends, Obama said. And the world is still watching.
"We need you to get this right," Obama said. "And what's more, you set an example for those who seek a peace of their own. ... And they're groping to find a way to discover how to move beyond the heavy hand of history, to put aside the violence. They're studying what you're doing. And they're wondering, perhaps if Northern Ireland can achieve peace, we can, too. You're their blueprint to follow. You're their proof of what is possible -- because hope is contagious."
Ultimately, he said, peace isn't about politics.
"It's about attitudes; about a sense of empathy; about breaking down the divisions that we create for ourselves in our own minds and our own hearts that don't exist in any objective reality, but that we carry with us generation after generation," he said.
Obama said the histories of Northern Ireland and the United States were "bound by blood and believe, by culture and by commerce. And our futures are equally, inextricably linked."
The United States has supported peace and prosperity in Northern Ireland for decades, he said. Because critical work remains, the United States will keep providing assistance in building a strong society, a vibrant economy and an enduring peace in Northern Ireland,he said.
As leaders move forward addressing challenges facing the country, they need young people "to keep pushing them ... to change attitudes," the president said.
"Because ultimately, whether your communities deal with the past and face the future united together isn't something you have to wait for somebody else to do -- that's a choice you have to make right now," he said. "The terms of peace may be negotiated by political leaders, but the fate of peace is up to each of us."
All young people in Northern Ireland must remind the world of the existence of peace and the possibility of peace, he said.
"You have to remind us of hope again and again and again," he said. "Despite resistance, despite setbacks, despite hardship, despite tragedy, you have to remind us of the future again and again and again."
When introducing her husband, U.S. first lady Michelle Obama said she doesn't see today's teenagers, she sees leaders of tomorrow.
"You all might just very well be some of the most important people that we talk to during our visits, because in just a couple of decades, you will be the ones in charge," the first lady said. "You'll be the ones shaping our shared future with your passion and energy and ideas."
"So when I look around this room, I don't just see a bunch of teenagers," she said. "I see the people who will be moving our world forward in the years ahead. And that's why we wanted to be here today."