BY HIS FAITH SHALL YE KNOW HIM:

[B]eing a Latter-day Saint is "at the center of who he really is, if you scrape everything else off," said Randy Sorensen, who worshiped with Mr. Romney in church.

As a young consultant who arrived at the office before anyone else, Mr. Romney was being "deseret," a term from the Book of Mormon meaning industrious as a honeybee, and he recruited colleagues and clients with the zeal of the missionary he once was. Mitt and Ann Romney's marriage is strong because they believe they will live together in an eternal afterlife, relatives and friends say, which motivates them to iron out conflicts.

Mr. Romney's penchant for rules mirrors that of his church, where he once excommunicated adulterers and sometimes discouraged mothers from working outside the home. He may have many reasons for abhorring debt, wanting to limit federal power, promoting self-reliance and stressing the unique destiny of the United States, but those are all traditionally Mormon traits as well.

Outside the spotlight, Mr. Romney can be demonstrative about his faith: belting out hymns ("What a Friend We Have in Jesus") while horseback riding, fasting on designated days and finding a Mormon congregation to slip into on Sundays, no matter where he is.

He prays for divine guidance on business decisions and political races, say those who have joined him. Sometimes on the campaign trail, Mr. and Mrs. Romney retreat to a quiet corner, bow their heads, clasp hands and share a brief prayer, said Representative Jason Chaffetz, a Utah Republican who has traveled with them.

Clayton M. Christensen, a business professor at Harvard and a friend from church, said the question that drove the Sunday school classes -- how to apply Mormon gospel in the wider world -- also drives Mr. Romney's life. "He just needs to know what God wants him to do and how he can get it done," Mr. Christensen said.

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