VATICAN CITY (CNS) -- The spiritual retreat Pope Francis offered priests and seminarians as part of the Jubilee of Priests could be seen as a "crash course" on the role of mercy in priestly ministry.

His series of three meditations in three Roman basilicas June 2 and Mass June 3 were to be "a full immersion because Pope Francis' heart is immersed in the heart of Jesus the Good Shepherd," said Archbishop Jorge Patron Wong, secretary of seminaries at the Congregation for Clergy.

The pope wanted the jubilee for priests and seminarians to be a time to step back from busy schedules and "find a bit of respite, relief, solace in the heart of the Good Shepherd, in the arms of the good Lord's mercy," the archbishop told Vatican Radio.

The three days of prayer, reflection and liturgies aim to help priests sharpen their focus on Christ and his infinite love and mercy, and recall that all graces and gifts received were given "not because we are great or worthy of his love, but because he is merciful," the archbishop said.

In his meetings with clergy, homilies and through his own lived example, Pope Francis has already given priests clear standards and concrete advice, filling some with a mixture of inspiration and fear.

"You certainly brought about a Copernican Revolution" for the church with this new manner of speaking, living and interacting with people, one priest told the pope during a Q&A in Caserta, Italy, in 2014.

Because, he said, the pope was triggering an existential crisis for priests, he asked what they needed to do to be the right kind of pastor for the third millennium.

While the priest lamented that the church always seems behind the times, the pope disproved the image of a revolution, saying the energy needed to bring God's mercy to the world is not about upheaval, but about revolving always and every day around Christ.

The priestly ministry is centered on Christ, and past popes have focused on very different, yet interlocking, aspects of the Good Shepherd when they've talked about the role of the priest.

St. John Paul II liked to emphasize holiness -- God's "incessant call to sanctification" and the need to strive to be saints.

His own priestly ordination fell on the feast of All Saints and, celebrating his 50th anniversary Nov. 1, 1996, he explained how ordination gives priests the unique power to bring the sacraments to the people, which helps them on their path to leading holier lives.

"The priest exists to offer the faithful the means Christ made available for this journey of progressive sanctification," he said. By offering the sacraments, "the priest becomes the servant of sanctity and communion of the baptized."

Pope Benedict XVI often emphasized the priests' special familiarity with and dedication to God's truth. The priest, as pastor, was to guide the faithful along the right path that leads to true joy and happiness.

"As priests we must communicate to people the joy for the fact that the right way in life has been shown," he said, concluding the Year for Priests in 2010.

The Good Shepherd, for Pope Benedict, was also a strong fearless guardian. The shepherd's staff must be used, he said, to "protect the faith against counterfeiters, against tendencies that are, in reality, disorienting." And the staff is also strong support to help one "walk on difficult paths and follow the Lord."

Yet that strength and determination are found in humility and tireless service, he showed, when he held up St. John Vianney -- the patron saint of parish priests -- as the role model for priests.

"The Cure of Ars was very humble," he said in his letter declaring the Year for Priests. "A good shepherd, a pastor after God's heart, is the greatest treasure which the good Lord can grant to a parish, and one of the most precious gifts of divine mercy," he quoted the priest as saying.

So many of the virtuous qualities Pope Benedict highlighted in St. Vianney mirror the same things Pope Francis has been underlining.

The French priest was "a great hospital of souls;" he was available day and night for his people, "ready to listen and offer forgiveness"; he knew it was not the sinner who returns to God, but "God who runs after the sinner and makes him return to him," Pope Benedict wrote in his letter.

Pope Francis told priests in Rome that his focus on mercy comes from St. John Paul, who had the prophetic intuition "that this was the time for mercy," and that "slowly it progressed" from there.

There are no new recipes for being good pastors, Pope Francis told clergy and pastoral workers in Assisi in 2013.

But there are many qualities different popes have pinpointed such as saints, sages and servants. Each pope continues to call on priests to carry on the fullness of Christ's ministry on earth with the sacraments, the truth and God's infinite love.

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