At the start of the 13th century, in a crumbling wayside chapel in central Italy, a penitent spendthrift was praying before an ancient crucifix when he heard a voice speak to him: "Go, Francis, and repair my house, which as you see is falling into ruin."

The young man took the divine command to heart, and in one of the most enduring conversion stories of Christianity, Francesco Bernadone - later known as St. Francis of Assisi - renounced his worldly belongings and devoted himself to a life of poverty and service. He gathered around him a group of like-minded mendicants, and founded a religious order that would help reform a medieval church plagued by corruption in Rome, sexual sins among the clergy, and social upheaval among the laity.

Some 800 years later, one of his spiritual descendents, a Franciscan friar named Sean Patrick O'Malley, invoked the same phrase as he accepted one of the most daunting jobs in the Catholic universe - head of the Archdiocese of Boston - amid what is widely viewed as the greatest church crisis of modern times. "I ask you, and plead with you: Repair my church," O'Malley said, dressed in his trademark brown robe and sandals.

As the epicenter of the clergy sexual abuse scandal, Boston is both a bastion of American Catholicism and, conversely, its weakest link. As Boston goes, many believe, so goes the rest of the 65-million-strong U.S. church. That makes the choice of O'Malley, who will be installed at a solemn Mass on July 30, perhaps the most crucial appointment of John Paul II's lengthy pontificate. And it raises a question: Can a humble friar once again rescue the Catholic Church?

If the answer is yes, it may be due to the important but often overlooked differences between clergy. O'Malley is a member of a religious order; his predecessor in Boston, Cardinal Bernard Law, is a diocesan clergyman, taught to thrive in the competitive matrix of chancery culture.

The divergence between the religious and diocesan ranks of priests begins at the moment of ordination. Priests ordained to religious orders - such as the Franciscans, Dominicans, Jesuits, Carmelites and the like - take vows of poverty, chastity and obedience, while priests ordained to a geographical diocese make promises - not vows -- to remain celibate and to be obedient to their local bishop. Of course, implicit in those promises for diocesan, or "secular" clergy as they are known, is the expectation that they will live a simple, Christ-like life. And the vast majority do.

But it is also possible for diocesan priests to own a home, or to salt away investments or an inheritance for retirement. Father Andrew Greeley, for example, is a Chicago priest and best-selling author who has made millions off his popular novels. But he has liberally dispensed his earnings, donating close to $2.5 million to the archdiocese and to the University of Chicago, where he teaches. Order priests generally do not have that option, and surrender anything they inherit or earn to their community of monks or friars.

Besides this egalitarian orientation, religious order clergy also tend to dedicate their lives to the poor, the sick, and the marginalized, often in missionary postings overseas. By contrast, diocesan clergy are likely to staff parishes and keep the machinery of the diocesan running. O'Malley, for example, first became a bishop in the U.S. Virgin Islands, where he promptly moved out of the previous bishop's grand residence and focused on ministering to the poor. Early in his career as a priest in Washington, D.C., he moved into vermin-infested housing in a run-down neighborhood. That kind of solidarity with the downtrodden is a hallmark of many religious orders, and particularly of Franciscan life. While Cardinal Law was feared as the basso profondo voice of Catholic orthodoxy, O'Malley embodies St. Francis' famous motto, "Preach the Gospel at all times. If necessary, use words."

That statement (while likely apocryphal) neatly sums up the Franciscan spirit and helps explain O'Malley's compassionate approach to victims of clergy sexual abuse, which differs markedly from that of many of his fellow bishops. That became evident a decade ago when O'Malley was named to head the diocese of Fall River, Mass., then the focus of a previous round of sex scandals. O'Malley earned a reputation for listening patiently to abuse victims, often for hours, and for negotiating out-of-court settlements that even had plaintiffs' lawyers praising him.

Thus it was no surprise when he was sent to the Diocese of Palm Beach last year after its second bishop in a row resigned in a sex scandal. This time around, with Boston in dire straits, Rome is desperate for a savior for the American church-and its choice of O'Malley makes perfect sense. Still, it has surprised veteran Vatican hands-and O'Malley himself, who hoped for a missionary assignment in Latin America - in part because he was installed in Florida just a few months ago.

At his introduction in Boston last month, O'Malley quickly made a distinct and positive impression, not only by wearing his trademark Capuchin robe and sandals to his inaugural press conference, but also by heading straight to a meeting with abuse victims. He promised to work for quick settlement for the hundreds of outstanding claims: "We must step up to the plate. People's lives are more important than money." And he indicated he would avoid the Commonwealth Avenue mansion where Cardinal Law lived. "Obviously, as a Franciscan brother, I prefer to have the simplest quarters," said the man who invites people to call him Bishop Sean.

Such a move would be in keeping with O'Malley's track record, and again points to the difference between diocesan and religious clergy. When he went to Palm Beach last year, for example, O'Malley rejected the large home that each preceding bishop had enlarged, instead moving into a small convent and letting the nuns there use the larger quarters. That was the polar opposite of the tack taken by Bishop William Murphy, a onetime aide to Cardinal Law in Boston who was sent in 2001 to head Long Island's Rockville Centre diocese. Upon his arrival, he displaced six Dominican nuns from their quarters and spent $800,000 transforming it into a 5,000-square-foot apartment for himself and "visiting dignitaries" who would stay in the "cardinal's suite." "Mansion Murphy," as Newsday columnist Jimmy Breslin dubbed him, spent $120,000 of the diocese's money on three oriental rugs and a new dining room table just as a budget crunch was forcing cuts in church programs for the needy.

O'Malley's desire to have a relatively simple installation mass was also a departure from the pomp and pageantry that bishops generally encourage for such events. He has invited several victims of sexual abuse, as well as Cardinal Law. (Law declined, saying he feared he would be a distraction.)

This counter-cultural style is a hallmark of religious orders. They are historically the engines of church reform, and they are often as zealous toward themselves as they are in renewing the faith among others. In fact, O'Malley's own Capuchin branch of the Franciscans was begun in 1525 by an Italian friar who felt the original Rule of St. Francis to live humbly was not being followed closely enough. He started a community whose members could wear a beard, sandals without socks, and a brown habit with a long pointed hood, or cappuccio - the Capuchins thought the small, rounded hood that had come into vogue among Franciscans showed a slacking of religious zeal - as signs of their humility. It is the same garb O'Malley wears daily; he is the only one of the more than 400 bishops in the U.S. hierarchy to wear a habit.

More than monastic rigor, the freedom to reform is a result of the traditional place of religious orders as outsiders. This dynamic can be seen at the local level, in the disproportionate number of religious orders running Catholic schools and soup kitchens and parishes in poor neighborhoods. Diocesan priests, on the other hand, with their close ties to the bishop, often seek plum assignments in wealthier, burgeoning parishes.

The lack of access to ecclesial power also translates into a lack of promotions to bishop for religious order clergy. Today, as in the past, more than 90% of all bishops in the American hierarchy are drawn from diocesan clergy. One study found that some 80% of all bishops had canon law degrees, vital tools for running a diocese but rarely a priority for order priests. And these diocesan priests who became bishops often earned those degrees in Rome, an experience that gained them contacts with Vatican officials and with bishops who might later aid their careers. In a 1983 study, the Rev. Thomas Reese, a Jesuit who studies the organizational church, found that just one-third of U.S. bishops had ever worked in a parish before promotion to the hierarchy. At the time, Reese found that less than 8% of the hierarchy were members of religious orders, even though order priests made up 40% of the priests in the United States. That ratio remains. Out of 410 active and retired bishops today, just 38 are members of religious orders.

None of this is to say that order priests are somehow "holier" than diocesan clergy. History is full of authoritarian Franciscans as well as saintly diocesan priests and bishops. Moreover, it is important to make room for variety in religious life. The popular impression that every priest must be an ascetic living in a dank cell does not mesh with every priest's vocation or temperament.

But it is true that religious order priests can bring a fresh personal approach when they become bishops. In today's church, that's vital. American Catholics are more furious at the way the church was managed by men like Law, who shielded abusive priests, rather than at particular church teachings. Archbishop O'Malley is certainly as orthodox as Cardinal Law on matters of sexual teachings and abortion, for example. Yet they are poles apart in how they relate to the faithful - a relationship that, if cultivated, can be the shortest avenue to resolving the crisis.

The solution is also not simply a matter of appointing more bishops from religious orders. In fact, religious orders have suffered even steeper declines in vocations than the diocesan priesthood, a drop-off of 30% since 1965. There are now fewer than 15,000 religious order priests in the United States versus 30,000 diocesan clergy, the lowest ratio in decades.

Rather, what is important in this penitential era of Catholicism is that the people-centered approach of priests like O'Malley remains a sign to all clergy, and especially to bishops representing the official church in a hostile environment. In this daunting situation they may do well to remember the advice of the English Cardinal Basil Hume, a Benedictine who died in 1999: "A monk is valuable in the market-place if he preserves a nostalgia for the desert."