The image of Obama as someone who draws heavily on faith to guide his daily life contrasts with his public persona.
An intensely private person, Obama has shied away from all but the most general descriptions of his spiritual life.
Obama had to distance himself from his longtime pastor, the Rev. Jeremiah Wright, when his anti-American rantings threatened Obama's 2008 presidential campaign.
Persistent and false claims that Obama is secretly a Muslim have followed him even into his second term.
"Sometimes I search Scripture to determine how best to balance life as a president and as a husband and as a father," Obama said in February at the National Prayer Breakfast. "I often search for Scripture to figure out how I can be a better man as well as a better president."
The best clues to which texts fortify Obama's spiritual consumption may come from the daily devotionals that DuBois started sending Obama, then a U.S. senator from Illinois, in 2008.
DuBois ran religious outreach for Obama's presidential campaign that year, and his digital benedictions for Obama have been compiled in a forthcoming book, "The President's Devotional."
"A snippet of Scripture for me to reflect on," Obama has said. "And it has meant the world to me."
At pivotal moments in Obama's presidency, DuBois sometimes selects texts that offer lessons appropriate to the challenges at hand.
Before one State of the Union address, it was the words of Isaiah, in an appeal for clarity of speech: "So shall my word be that goes out from my mouth, it shall not return to me empty, but it shall accomplish that which I purpose."
Others are intended as an oasis from the conflicts Obama confronts on any given day.
"We are hard-pressed on every side, but not crushed. Perplexed, but not in despair," reads a verse from 2 Corinthians that DuBois sent Obama one November, followed with his own meditation: "Dear God, give us a resilient spirit, a spirit that returns to face this day even in the shadow of yesterday's challenges. Help us, today, to bounce back."