In the hardest of moments, we find the deepest of truths.

In the countless Bostonians who offered shelter to strangers or blood to the wounded, we've witnessed that abiding identifier of American spirit — our desire to relieve the suffering of strangers. In Boston this week, as in New York after 9/11, you could simply not escape this pure but simple idea: They are of us and they need our help. That compassion is the root of why America is the most charitable nation on Earth. We are a good and decent people.

We've also seen astonishing courage. In the years to come, as we celebrate future marathons, we'll of course never forget what happened in Boston. But our memories won't just be fixated on the horror of wounded bodies. Just like flight 93, there will be an enduring and inspiring record of those who rose to the moment. In the police officers, soldiers, and bystanders who ripped down barricades and went door to door and gave their lives, in the EMTs and doctors who worked relentlessly to preserve life. And in the runners, who, after 26 miles of brutal physical endeavor, turned and ran into the smoke to rescue strangers.

And even though it might not last, for a time at least, our political rancor faded. Boston proved that the foundations of American government remain firm. We took comfort in the FBI press conferences. We kept trust in our great offices of state. When it came to Boston, there were no Republicans and Democrats, just American leaders.

But perhaps this is the most powerful truth of Boston: At the crucial core of our identity, the divisions between us are paper thin. Red Sox fans like me will never forget the support of our coastal neighbor (and hated rival), the New York Yankees. But for all our teams' bitter history, in those two minutes in which Yankees fans sang Boston's "Sweet Caroline," Red Sox Nation and our entire nation saw a clear and certain truth. Whatever our creed, whatever our regional allegiance, whatever our color, whatever our politics, we are one people. We are a people individually diverse but unbreakably united.

It's true, of course, that this week has also shown our national flaws. In our desire for quick and easy resolutions to extraordinarily complex challenges, we saw media mistakes and innocent people wrongly blamed. And this much bigger problem: As a country, we have to accept that for all the joys our freedoms bring, there will always be those who exploit those very freedoms to do harm to others. Whether organized groups or lone wolves, sometimes terrible desire will meet awful capability. So as we strive to defend ourselves, we must also accept another harder truth: Monday is unlikely to be the last or the worst act of terrorism that America suffers.

For all our flaws, we are a great and noble people. And so, even as we remember the lost, we should continue forward with renewed faith and emboldened spirit.

This week, as on April 19, 1775, Boston again showed us that America is worth fighting for.