President Obama delivers a eulogy for the Rev. Clementa Pinckney in Charleston, S.C. REUTERS/Brian Snyder

“This whole week, I’ve been reflecting on this idea of grace,” said President Obama today, just before he broke into song at the funeral for South Carolina State Sen. Clementa Pinckney, a pastor killed along with eight others in last week’s Charleston, S.C., church shooting. The song Obama sang, of course, was “Amazing Grace.”

Obama isn’t the first president to speak about the concept of grace. One of my favorite quotes about grace is by John F. Kennedy, who said, “I look forward to an America which will not be afraid of grace and beauty.” But this was an exceptional moment, when a president spoke at length about something so tender, so ephemeral and so difficult to describe that we don’t ever talk much about it. Obama chose this occasion for a surprisingly profound exploration of what grace means here, today, and for all of us.

We all come to the word “grace” with different perceptions. But whether we think of divine love, or easy, elegant movement, or gentle and welcoming behavior, at the root of these ideas is a sense of joyous giving — a giving of oneself to something greater. In his eulogy, Obama directed us to the graceful generosity that characterized Pinckney’s life.

President Obama brought mourners to their feet during his eulogy of South Carolina state Sen. Clementa Pinckney as he sang a verse from the song "Amazing Grace." (Video: The Washington Post)

“Reverend Pinckney … conducted himself quietly and kindly and diligently,” said the president, speaking on the College of Charleston’s campus. “He encouraged progress not by pushing his ideas alone but by seeking out your ideas, partnering with you to make things happen.

“He was full of empathy and fellow feeling, able to walk in somebody else’s shoes and see through their eyes,” Obama said. That’s a perfect description of grace. As spiritual leaders, philosophers and humanitarians through time have shown us, being able to feel what others feel, see things from their perspective, is at the essence of grace. You forget yourself and reach out to others. (Gandhi, Eleanor Roosevelt, Nelson Mandela: all experts at getting out of their own heads and making deep connections with others.)

That sense of physically reaching out, leaning toward other people, is embedded in the word “grace.” We get it from the Latin gratia, which came from the Greek charis, which originally meant “favor,” as in a gift or act of kindness that one person extends to another, in a gesture of offering.

It’s no wonder, Obama continued, that one of Pinckney’s Senate colleagues remembered Pinckney as “the most gentle of the 46 of us, the best of the 46 of us.”

[Read the transcript of Obama’s eulogy.]

“What a good man,” he added. “Sometimes I think that’s the best thing to hope for when you’re eulogized, after all the words and recitations and resumes are read, to just say somebody was a good man.”

Obama expanded his meditation on grace to include a wider circle of goodness and giving. He spoke of  “the grace of the families who lost loved ones; the grace that Reverend Pinckney would preach about in his sermons; the grace described in one of my favorite hymnals, the one we all know — Amazing Grace.

“According to the Christian tradition,” he continued, “grace is not earned. Grace is not merited. It’s not something we deserve. Rather, grace is the free and benevolent favor of God.”

This is true of many other religions — Judaism and the Islamic tradition, for example — that hold dear the idea of freely given compassion as a divine quality.

I’m fascinated by grace, and I’ve written a forthcoming book about it, “The Art of Grace.” This is why I was so astounded to hear Obama sing “Amazing Grace” and read his eloquent words on a subject that just isn’t discussed and explored in such a public way anymore. He’s right to bring it up, to show us how grace can be perceived, and that it is worth noticing. Grace is an ancient notion, and it has a kind of universal hold on us — whether we’re religious or not, many of us relate to the idea of grace as a comfort to the soul, a form of love, a way to get through difficulty. Being human can hurt. It hurts because we are — most of us — compassionate creatures. We are linked to one another in the way that animals, say, are not. We can hear about a senseless shooting in a church miles away and feel our hearts drop on the floor.

But if we didn’t feel this pain, we wouldn’t also feel the comfort. Perhaps this explains why “Amazing Grace,” surely one of the best-known songs in the English-speaking world, is so uplifting. I find it has an uncannily graceful way of blending a verbal message of hope with the living sensation of it. I can’t hear that song without feeling some stir of longing or resolve.

Resolve, in fact, is what Obama so expertly tapped into, in the most powerful part of his eulogy. I don’t mean his singing, which was quite lovely, or his voicing of a hope that we may all be worthy of God’s grace. The capstone was the way he expressed his final wish: a wish for God’s grace on the United States of America–pausing to place emphasis on “united.”

That word had a force to make you shiver, because of the way Obama had led up to it. One man’s generosity, one community’s sacrifice and forgiveness, one overarching power urging us to “find our best selves” — and now one nation, united in all of those: generosity, sacrifice, love.

For that is indeed the most amazing grace, the kind that can bring us together in the shared experience of our own humanity. Even — and especially — when being human hurts.