The German Bishops' Conference rejected a Nazi comparison made by the Swiss Curia Cardinal Kurt Koch with unusual sharpness.

"The general assembly of bishops reacted with horror to this statement, with which Cardinal Koch disqualifies himself in the theological debate," said the chairman of the bishops' conference, Georg Bätzing, on Thursday in the final press conference for the autumn general assembly of bishops in Fulda.

It is a "completely unacceptable derailment".

Bätzing demanded an immediate public apology from Koch and otherwise threatened an official complaint to the Pope.

Koch is an influential member of the Roman Curia.

In an interview with the conservative Catholic "Tagespost", the former bishop of Basel commented on the extent to which Catholic teaching could be further developed and adapted on the basis of new findings.

He said: “It irritates me that new sources are accepted in addition to the sources of revelation of Scripture and tradition;

and it frightens me that this is happening – again – in Germany.

Because this phenomenon already existed during the National Socialist dictatorship, when the so-called "German Christians" saw God's new revelation in blood and soil and in the rise of Hitler."

Bätzing said Koch has been trying for some time to delegitimize the current reform project of German Catholics, the Synodal Way.

He described the majority of the members of the Synodal Assembly as officials.

"In the interests of the cause and in the interests of the faithful of the Catholic Church in Germany who are involved in the synodal path, I expect Cardinal Koch to make a public apology for this completely unacceptable way of wording," said Bätzing.

"If this public apology is not made promptly, I will make an official complaint to the Holy Father."

Koch's statements - though unprecedented in tone - do not stand alone but form part of a series of attacks by the Vatican against the synodal path.

Most recently, the papal ambassador in Berlin, Nikola Eterović, warned the bishops against "parliamentarianism" in a greeting at the beginning of their meeting in Fulda.

He also reminded them that the Vatican had recently declared that the Synodal Way had "no authority" to change the governance structure or the teaching of the Church.

The synodal path strives for changes in four areas: the role of women in the church, Catholic sexual morality, dealing with power and priestly celibacy.

Bätzing said that Koch's statements ultimately speak of "pure fear that something will move".

However, he could promise: "Something will happen, and Cardinal Koch will also be able to stop that - certainly not through such statements." The German Catholics are by no means alone with these concerns.

The submissions for the World Synod convened by Pope Francis showed that these issues are also acute in many other countries.

For decades, none of this was addressed and suppressed, but that is changing: "The pressure is so great that there is also such strong emotionality when the plug finally flies out, it's really no wonder."

At the fourth synodal assembly earlier this month in Frankfurt/Main, one of the basic texts for the renewal of Catholic sexual morality failed because it did not receive the necessary two-thirds majority from the German bishops.

The fact that there are also conservatives among the bishops who cannot support the desired reforms is not surprising, said Bätzing: "As a bishops' conference, we are no different than society as a whole." The bishops "actually have a consensus that it there is dissent and that we want to deal with it well".

With the synodal path, "with all our argumentative and spiritual strength, we present proposals for changes in church life in our own country," said Bätzing: "Synodality is the crucial hinge on which everything hangs."

The reform project is to be completed with the fifth synodal assembly in March.

The German Catholics then want to implement some of the reforms themselves on their own responsibility and pass on fundamental questions to the world synod planned in Rome for further discussion.

The synodal discussion between bishops and lay people in Germany should be continued in the long term.