In this week's Sunday Spotlight, Pentecostal preacher Joshua DuBois explains his unique relationship with President Barack Obama and the story behind his new book, "The President's Devotional," which archives the spiritual devotionals DuBois personally sent to the president on a daily basis.

The emails began in 2008, when DuBois, who is former head of the White House Office of Faith-based and Neighborhood Partnerships, was the religious outreach coordinator for then-Senator Obama's presidential campaign. He hadn't been asked to do so, but DuBois took a chance and sent a spiritual email directly to Obama's Blackberry. DuBois told ABC's Cokie Roberts why he decided to share his private prayers with Obama.

"I was wondering, you know, who was thinking about his spirit? Who was thinking about his soul?" DuBois said on "This Week." "Instead of praying for him privately, why don't you reach out to him and send him an e-mail with a word of encouragement. Within a few minutes, [Obama] wrote back and said, 'This is exactly what I've been looking for.'"

ABC News

From then on, it became a daily ritual, which President Obama said "has meant the world" to him. DuBois says he hopes his emails better enabled the president to tackle challenges with a greater measure of peace, even in situations of unthinkable tragedy, like when President Obama met with the Newtown shooting victims' families.

"The president wanted me to go with him to meet with the families… and try to give some level of comfort to them," DuBois said. "There were a number of parents who had pulled out the school pictures that they had just taken, and pointed to them and then just collapsed."

"The president just had to hold them," DuBois continued. "I was proud of him, but it was also one of those moments where I was really kind of just concerned for his spirit."

DuBois' emails aimed to boost the president's spirits, but some also served as reminders to do the right thing. "Hold your peace" and "love your enemies" were two common themes.

"It's so much better to learn to love our enemies," DuBois said. "We'll be able to get so much more done."

Read an excerpt from "The President's Devotional" here.

Like "This Week" on Facebook here . You can also follow the show on Twitter here .

Go here to find out when "This Week" airs in your area.