With his wife Michelle, Vice-President Biden, and many other Washington dignitaries looking on, he spoke with some humility of his place in God's created order.
"No matter how much responsibility we have, how fancy our titles, how much power we think we hold, we are imperfect vessels. We can all benefit from turning to our Creator, listening to Him. Avoiding phony religiosity, listening to Him," he noted.
Despite enormous demands for his time, the president said his daily routine includes a short devotional at the start of the day. "I wake up each morning and I say a brief prayer, and I spend a little time in scripture and devotion."
President Obama mentioned personal phone calls, visits and prayers with two influential spiritual leaders: Joel Hunter, a mega church pastor from Florida, and with T.D. Jakes, a mega church pastor from Texas.
The president said his personal faith often guides his public policy choices. "When I decide to stand up for foreign aid, or prevent atrocities in places like Uganda, or take on issues like human trafficking, it's not just about strengthening alliances, or promoting democratic values, or projecting American leadership around the world, although it does all those things and it will make us safer and more secure. It's also about the biblical call to care for the least of these –- for the poor; for those at the margins of our society.
Even sincere believers will disagree about politics, he said, quoting C.S. Lewis: "Christianity has not, and does not profess to have a detailed political program. It is meant for all men at all times, and the particular program which suited one place or time would not suit another."
"Our goal should not be to declare our policies as biblical. It is God who is infallible, not us. Michelle reminds me of this often," President Obama said.
The president took note of a gathering of young people in Atlanta known as the Passion Conference, which raised several million dollars to fight human trafficking. "Last month, it was inspiring to see thousands of young Christians filling the Georgia Dome at the Passion Conference, to worship the God who sets the captives free and work to end modern slavery.
One consistent theme President Obama pressed is to live out one's faith in an authentic way.
"I think we all understand that these values cannot truly find voice in our politics and our policies unless they find a place in our hearts. The Bible teaches us to 'be doers of the word and not merely hearers.' We're required to have a living, breathing, active faith in our own lives. And each of us is called on to give something of ourselves for the betterment of others â€" and to live the truth of our faith not just with words, but with deeds.
President Obama quoted from the Book of John to encourage help for the poor, "If anyone has material possessions and sees his brother in need but has no pity on him, how can the love of God be in him? Dear children, let us not love with words or tongue but with actions and in truth."
On April 25, 2010, the president had a private meeting with Rev. Billy Graham, which left a big impact on his faith.
"I can still remember winding up the path up a mountain to his home," Pres. Obama recalled. "Ninety-one years old at the time, facing various health challenges, he welcomed me as he would welcome a family member or a close friend."
"Before I left, Reverend Graham started praying for me, as he had prayed for so many Presidents before me. And when he finished praying, I felt the urge to pray for him.
Remarkably, when it was the president's turn to pray, he felt tongue-tied, but the Holy Spirit made provision for his words. "I didn't really know what to say. What do you pray for when it comes to the man who has prayed for so many? But like that verse in Romans, the Holy Spirit interceded when I didn't know quite what to say."
"And so I prayed â€" briefly, but I prayed from the heart. I don't have the intellectual capacity or the lung capacity of some of my great preacher friends here that have prayed for a long time. But I prayed. And we ended with an embrace and a warm goodbye," President Obama said.
These moments with Graham led to some introspection by the president. "I thought about that moment all the way down the mountain, and I've thought about it in the many days since. Because I thought about my own spiritual journey –- growing up in a household that wasn't particularly religious; going through my own period of doubt and confusion; finding Christ when I wasn't even looking for him so many years ago; possessing so many shortcomings that have been overcome by the simple grace of God."
The visit with Graham also led to greater passion in his devotional life. "I have fallen on my knees with great regularity since that moment â€" asking God for guidance not just in my personal life and my Christian walk, but in the life of this nation and in the values that hold us together and keep us strong. I know that He will guide us. He always has, and He always will."