For too many of us, it's become safer to retreat into our own bubbles, whether in our neighborhoods or on college campuses, or places of worship or especially our social media feeds, surrounded by people who look like us and share the same political outlook and never challenge our assumptions. And increasingly, we become so secure in our bubbles that we start accepting only information, whether it's true or not, that fits our opinions, instead of basing our opinions on the evidence that is out there.

We've been able to build up the Afghan security forces and stabilize it.

We remain a young nation, but in the words of Scripture, the time has come to set aside childish things. The time has come to reaffirm our enduring spirit; to choose our better history; to carry forward that precious gift, that noble idea, passed on from generation to generation: the God-given promise that all are equal, all are free, and all deserve a chance to pursue their full measure of happiness.

Over the last few years a lot of people have become aware of the inequities in the criminal justice system, right now, with our overall crime rate and incarceration rate both falling, we're at a moment when some good people in both parties, Republicans and Democrats and folks all across the country, are coming up with ideas to make the system work smarter and better.

But it will depend on young people like you being open to new ideas and new possibilities. And it will require young people like you never to stereotype or assume the worst about other people.

Let us remember that we can do these things not just because of wealth or power, but because of who we are: one nation under God, indivisible, with liberty and justice for all.

If we're going to prevent large parts of this Earth from becoming not only inhospitable but uninhabitable in our lifetimes, we're going to have to keep some fossil fuels in the ground rather than burn them and release more dangerous pollution into the sky.