With the notable absences of Mitt Romney and Jon Huntsman, the discussion turned uncharacteristically personal, with the would-be presidents tearfully revealing formative chapters that shaped their faith.
The evening at the event sponsored by an Iowa Christian group was both predictable and surprising. Predictable for the social and political causes the candidates embraced in front of the gathering of religious conservatives.
On abortion, Gov. Rick Perry said, "that we are sending billions of dollars to China who are aborting 35,000 children a day, is immoral and wrong and has to stop."
But the evening was also surprising for the personal feelings that were revealed. First there were the journeys of personal faith.
"It wasn't until I was 16 that I gave my life to the lord," said Minnesota Rep. Michele Bachmann.
Then the questions about personal failings and what each had learned from them exposed the rawest emotions.
Former Pennsylvania Sen. Rick Santorum talked about his struggles coping with the life-threatening illness of his 3-year old daughter.
"I decided that the best thing I could do was to treat her differently and not love her, like I did, because it wouldn't hurt as much if I lost her," he said.
Businessman Herman Cain broke down remembering the loyal support of his wife when they learned he was fighting for his life with stage four cancer.
"I said, 'I can do this.' She said, 'We can do this,'" said a teary-eyed Cain.
All the candidates, including Romney and Huntsman, will go at it again Tuesday. This time, the debate will be less personal and emotional as the topic turns to foreign policy.
The Associated Press contributed to this story.