ROME — Between Pope Francis and retired Pope Benedict XVI, there is “continuity of magisterium and particularity in pastoral style,” but even more, there is “a living communion of affection,” said Cardinal Pietro Parolin, Vatican secretary of state.

What retired Pope Benedict XVI once described as the importance of “newness and continuity” in the teaching of the Second Vatican Council compared to the past also can be seen in comparing the teaching of the two popes, Parolin wrote in the introduction to “Una Sola Chiesa,” (“Only One Church”).

The book, released Sept. 1, demonstrates continuity by presenting excerpts of general audiences talks from Pope Benedict and Pope Francis on the themes of church, family, prayer, faith and mercy.

Published in Italian by Rizzoli, the volume lists the authors as the two popes; there is no indication who chose the passages, but the publisher says the idea for the book came from Msgr. Giuseppe Scotti, former president of the Joseph Ratzinger-Benedict XVI Foundation.

Parolin noted that in solemnly opening the Second Vatican Council, St. John XXIII said its purpose was “to transmit Catholic doctrine, pure and integral, without any attenuation or distortion,” but to do so in a way that demonstrates how it responds to the needs and questions of modern men and women.

St. Paul VI felt the same way, as did St. John Paul II and Pope Benedict, the cardinal said. “And the continuity of the papal magisterium is the furrow followed and carried on by Pope Francis, who in the most solemn moments of his pontificate always recalls the example of his predecessors.”

“In the case of Benedict XVI and Pope Francis,” he said, “the natural continuity of the papal magisterium has a unique trait: the presence of a pope emeritus in prayer next to his successor.”

And they speak about each other with affection, identifying traits that continue to build up the church, he said.

A case in point, he said, was the celebration in June 2016 of the retired pope’s 65th anniversary as a priest.

Pope Francis told him, “You, Your Holiness, continue to serve the church, and you never cease to contribute with vigor and wisdom to her growth, and you do so from that little monastery of Mater Ecclesiae in the Vatican Gardens.”

From the retired pope’s monastery residence, Pope Francis said, there “emanate a tranquility, a peace, a strength, a trust, a maturity, a faith, a dedication and a fidelity that helps me so much and that gives such strength to me and to the entire church.”

Thanking Pope Francis, Pope Benedict replied, “Your goodness, evident from the moment of your election, has continually impressed me, and greatly sustains my interior life. The Vatican Gardens, even for all their beauty, are not my true home: my true home is your goodness. There, I feel safe. Thank you also for the kind words of gratitude, for everything. We hope that you will continue to go forward with all of us on this road of divine mercy, showing us the way of Jesus, toward Jesus, toward God.”

By presenting the teaching of Pope Francis and retired Pope Benedict side by side, Parolin said, the book provides a primer on “faith, the church, the family, prayer, truth and justice, mercy and love.”

“The spiritual consonance of the two pontiffs and the diversity of their communicative style multiply the perspectives and enrich the experience of the readers — not only the faithful but all the people who, in an era of crisis and uncertainty, recognize in the church a voice capable of speaking to their needs and aspirations,” the cardinal wrote.