When retired Pope Benedict XVI resigned from the papacy in 2013, he said that he would be “hidden from the world,” and that God was calling him “to go up the mountain,” and to dedicate himself to prayer and meditation.

However, it became clear on Sunday that his idea of “hidden” is not quite the dictionary definition when excerpts of a new book by Benedict and Guinean Cardinal Robert Sarah, the head of the Vatican’s liturgy office, were published in French daily Le Figaro.

Titled From the Depths of Our Hearts: Priesthood, Celibacy and the Crisis of the Catholic Church, the book is set to be published in full Jan. 15, and consists of a chapter by each of the authors, as well as a jointly written introduction and conclusion.

Notably, the book, which issues a firm defense of clerical celibacy from both authors, comes as Pope Francis is considering a proposal from the October 2019 Synod of Bishops on the Amazon on whether to allow married men to be ordained to the priesthood in certain limited cases.

Reaction to the book exploded, not only because Benedict’s comments come as his successor is deliberating a major decision on the same topic, but also because it is published under Benedict’s papal name, making no reference to his status as “emeritus.”

Catholic insiders immediately took to social media insisting on the need for clarification on the role of an emeritus pope, with many saying Benedict had “broken his silence.”

In a series of tweets published Jan. 12, Kurt Martens, a professor of canon law at the Catholic University of America, said he looked forward to reading the book, but stressed the need “to recall that there is only one Pope, one Bishop of Rome: Francis. He and he alone has the power associated with the office of Bishop of Rome.”

“There is a huge mistake on the cover: this is not a book by ‘Benedict XVI’. This is a book written by an emeritus and the cover should have indicated that. It would have been more appropriate to publish as ‘Joseph Ratzinger,’” he said.

“A former pope should not speak in public about anything at all. He had his chance when he was in office. Now it belongs to his successor to govern. He (and his entourage) no longer governs,” Martens said, noting that canon 273 in the Code of Canon Law imposes “a special obligation on clerics (deacons, priests, and bishops, thus also including Joseph Ratzinger): they all are bound by a special obligation to show reverence and obedience to the Supreme Pontiff.”

Similarly, John Gehring, Catholic program director for Faith in Public Life and a Commonweal contributor, said in a tweet that having one pope “is complicated enough. This is a mess.”

“With great respect to Benedict XVI, it’s time for him to live up to his promise to be ‘hidden from the world,’” he said.

Italian journalist Salvatore Cernuzio of Vatican Insider also weighed in via Twitter, noting that while Benedict in his final Angelus address of 2013 said he would dedicate the remainder of his life to prayer, in the seven years that have passed, Benedict has given interviews and published letters, lengthy essays, and now a book.

Opinions on whether it is appropriate for an emeritus pope to make public comments on a decision that the current pope is deliberating were vast, breaking along predictably ideological lines.

In comments to Crux, papal biographer and Francis enthusiast Austen Ivereigh said he believes it is “massively imprudent” for a retired pope to intervene when his successor is about to make an important decision on a given topic.

While Benedict is free to speak out as he wishes, “to do so in this way at this time,” Ivereigh said, “looks like he’s putting political pressure on Francis” and to “undermine” his authority.

“In my understanding, Francis is actually reluctant to endorse the proposal to ordain married deacons” as priests, he said, adding that should Francis reject the proposal now, the decision could be painted as having been made under Benedict’s influence, rather than autonomously.

Ivereigh voiced his opinion that Benedict, in making his comments on priestly celibacy now, is being “manipulated” in a “highly-controlled operation” by Francis opponents.

“I know he’s lucid, but he’s so frail that he can’t possibly have judged this himself to be prudent,” Ivereigh said, adding that sources have told him Benedict, 92, is hardly able to speak above a whisper and has difficulty staying awake for more than 30 minutes at a time.

Ivereigh noted that when the latest round of new cardinals visited Benedict XVI in October, the retired pontiff stressed the need for loyalty.

“Benedict is barely able to say anything, and when he does, he says be loyal. Yet he’s done something that is totally disloyal, and that’s why I say he’s been used,” Ivereigh said, adding that he believes Francis’s last reform, if he himself resigns, “will be to reform the emeritus papacy.”

“Benedict himself clearly wanted something different” for himself, Ivereigh said, as he initially wanted to return to Bavaria, but was told he needed to stay inside the Vatican. Ivereigh voiced his belief that Benedict XVI, while having many fine qualities, has a “certain weakness” in allowing himself to be told what to do without question.

On the other side of the debate, veteran Italian journalist Sandro Magister, a known critic of Francis, told Crux that in his view, Benedict was not out of line, but rather, acted out of duty.

“The figure of ‘pope emeritus’ is not to be ‘rethought,’ but invented, because it has no precedent in history,” he said.

“Ratzinger is creating it with facts,” Magister said, voicing his belief that “the prudence of a pope emeritus in intervening on a question on which the reigning pope is deliberating depends entirely on the quality and severity of the matter.”

For Benedict, he said, “this severity is what obliges him (not only encourages him) to break his silence.”

While the debate on whether Benedict’s comments in the book are appropriate or not will likely continue for some time to come, perhaps the biggest question in all this is best put by Brazilian reporter Filipe Domingues of the G1 news site, who in a Jan. 12 tweet said that “It is forgotten more than ever, what makes us question which role the Pope Emeritus actually has in the Church.”

“Canonical clarification was necessary, now it is urgent,” he said.

This story incorporates reporting from AP.