In ways large and small, Barack Obama's visit to the Pastor Rick Warren Saddleback Church resembled a Christian taking on the lions. The audience, after all, was overwhelmingly predisposed to the Republican John McCain. To be sure, the questions posed by Warren had a purpose-driven life for the conservative agenda. And making matters even more difficult for Obama, Reverend Warren edited out scriptural references for McCain, a man notoriously uncomfortable speaking about matters of religious faith.
In theory, Warren was to pose the same questions to each candidate during their separate appearances on stage. But starting with the very first question to each man, Rick Warren made sure John McCain was treated with biblical kid gloves:

QUESTION TO OBAMA: These first set of questions deal with your personal life as a leader and I'm not going to do this with any other segment, but as pastor I've got some verses that have to do with leadership. The first issue is the area of listening. There is a verse in Proverbs that says fools think they need no advice but the wise listen to other people. Who are the wisest three people you know in your life and who are you going to rely on heavily in your administration?
QUESTION TO MCCAIN: This first question deals with leadership and the personal life of leadership. First question, who were the three wisest people that you know that you would rely on heavily in an administration?

Given the very different framing of the question Warren posed, it's no surprise that Barack Obama and John McCain produced strikingly different responses in both substance and style. Obama took Warren's personal question personally, and cited his wife and grandmother as both "wise and honest'' before moving on to a litany of political figures on both sides of the aisle. (Obama's mention of the radical social conservative Tom Coburn (R-OK) was transparent pandering to his audience.) For his part, McCain responded to Warren's political question and pointed to General David Petraeus, Obama supporter Congressman John Lewis and former eBay CEO Meg Whitman. (McCain was quick to return to his stump speech and extol the glories of eBay as America's economic future.)
But Warren's divergent paths for Obama and McCain split further with the very next question on leadership and moral weakness. Again, Warren turned to the Bible for Barack Obama, but to Dr. Phil for John McCain:

QUESTION TO OBAMA: Let's talk about personal life. The Bible says that integrity and love are the basis for leadership. This is a tough question. What would be looking over your life, everybody's got wings [sic], would be the greatest moral failure in your life and what would be the greatest moral failure in America?
QUESTION TO MCCAIN: We had a lot leaders because of their weaknesses, character flaws, stumbled, become ineffective [and] are not serving anymore, serving our country. What's been your greatest moral failure and what has been the - what do you think is the greatest moral failure of America?

Again, the different framing of the question put Obama at a distinct disadvantage. After admitting his own troubled, selfish youth as his personal failing, Obama turned to scripture to highlight America's failure to live up to its own ideals:

"I think America's greatest moral failure in my lifetime has been that we still don't live by that basic precept in Matthew that whatever you for the least of my brothers, you do for me."

In contrast, McCain killed two birds with one stone. He dispensed with his own marital infidelity in a single sentence, "my greatest moral failing, and I have been an imperfect person, is the failure of my first marriage." (The issue never surfaced again, and Warren's admission Friday that he "absolutely" would have compunctions about voting for an adulterer never became an issue for McCain.) More important, McCain highlighted America's greatest shortcoming as a failure to "serve cause greater than yourself." That theme - "country first" - is the rhetorical cornerstone of the McCain campaign. And the contrast of his response with Obama's discussion of his own battle with what Warren termed "fundamental selfishness" couldn't have been more strategic for McCain.
And so it went all night. Thanks in no small part to Pastor Warren's biblical guidance, Barack Obama spoke in a personal, conversational style, making a point throughout to refer to the principles of his Christian faith in the misguided attempt to please an audience indifferent to him at best, downright hostile at worst. So while Barack Obama talked "trying to do God's work," John McCain did the work of his campaign advisers. McCain just repackaged his stump speech in making purely political appeals, and in so doing, probably had the best night of the campaign.
UPDATE: Despite the obvious differences in Warren's framing of questions for Obama and McCain, CNN reported on the event in a piece titled, "Same Tough Questions, Different Approaches."