As biblical orthodoxy puts it, you cannot serve both God and mammon. Twenty-five years ago, having chosen to serve God and study theology, Justin Welby gave up an 11-year finance career that had seen him rise to the ranks of group treasurer with a major U.K. company, Enterprise Oil. Ordained as a priest in 1992, he was appointed Bishop of Durham just last year.

He is now the current front-runner to be the next Archbishop of Canterbury: the most senior cleric in the Church of England.

But this quiet, good-humored, and self-effacing bishop brushes off such suggestions, claiming not to be clever enough for such an exalted position. He recently said in an interview with the Guardian newspaper that he only “drifted into” finance after studying law and economic history at Cambridge University because he “could speak English and didn’t know anything about anything”: exactly the attributes his new employer was looking for, he said, so that it could mold him to its ways of working.

At theology college, Welby wrote a paper entitled, “Can Companies Sin?” Yes, he argued, they most certainly can. These days he speaks at conferences for finance executives on topics such as business ethics and ethical investment. In July he was asked to join a British parliamentary commission on banking standards. And he has spoken about how the “Occupy” movement is “absolutely right” in saying that something is very wrong with today’s world.

Welby still keeps in touch with his treasury roots: when the U.K. Association of Corporate Treasurers held its annual conference in Liverpool last year, he welcomed delegates to a dinner at the city’s cathedral where he was dean at the time. It was a splendid setting that looked like a feast out of Harry Potter’s Hogwarts.

The current Archbishop of Canterbury, Rowan Williams, retires at the end of this year. The special committee charged with looking for a successor is, under the arcane rules of the English establishment, expected to put forward to Prime Minister David Cameron the name of its preferred candidate and one other.

By many accounts, the committee has agreed that Welby is its first choice. It just can’t agree who should be the runner-up. If that’s so, then the Church of England may well soon have at its head a man who will have much to say about morality and the financial world: and who is very well versed in both.

Andrew Sawers is editor of CFO European Briefing, a CFO online publication.