Father Georgy Edelshtein is keen to debate those who disagree with his opposition to Russia's military campaign in Ukraine.
"I'd like to see one or two of my opponents sitting right here," the 89-year-old says, pointing to an empty armchair in his living room full of gilded icons.
The white-bearded priest in a black cassock is one of the few Russian Orthodox priests to have spoken out against Moscow's military operation in Ukraine.
In a quavering voice, but without hesitation, he explains: "I'm afraid I am a bad priest. I've never been against all wars but I've always been against any land-grabbing, aggressive war."
Ukraine "is an independent state and let them build their state as they see necessary," he tells AFP in his house in the hamlet of Novo-Bely Kamen on the banks of the River Volga in the Kostroma region, a six-hour drive from Moscow.
Since Russia launched its military action on February 24, only a handful of priests from the Russian Orthodox Church led by Moscow Patriarch Kirill -- which counts some 150 million believers across the world -- have spoken out openly against the Kremlin's military campaign.
Kirill has given a series of increasingly bellicose sermons, calling for Russians to "rally around" the authorities to help conquer "enemies" he accuses of trying to destroy historic unity between Russia and Ukraine.
Since he started heading the Church in 2009, Kirill has sought closer ties with President Vladimir Putin's government, backing conservative values over Western liberalism.
The Russian Orthodox Church was severely restricted and under KGB control in the USSR.
Even after the 1991 collapse of the Soviet Union it has never encouraged criticism of the authorities, but some priests are nevertheless speaking out.
- 'Blood on hands' -
On February 25, a day after the military operation began, Edelshtein signed a letter written by a priest friend, Father Ioann Burdin, that was posted on the website of Burdin's parish church in the village of Karabanovo in the Kostroma region.
"The blood of Ukrainian residents will remain on the hands not only of the rulers of Russia and soldiers carrying out this order. Their blood is on the hands of each of us who approve this war or simply remain silent," said the post, which was later deleted.
Metropolitan Ferapont of Kostroma, a highly placed monk, condemned the letter, saying that only two priests out of 160 in the region opposed the operation.
But their protests did not stop there.
On March 6, Burdin preached about the human cost of the ongoing fighting.
The very same day he was summoned for questioning by investigators.
On March 10, he was ordered to pay a fine of 35,000 rubles ($489/450 euros) for "discrediting" the armed forces, punishable by up to three years in prison for a repeat offence.
Four people testified against him in court.
"During the sermon, Father Burdin... told us that he was going to pray for Ukraine," a female parishioner said according to court documents seen by AFP.
- 'Satanist' -
Burdin, 50, continues to condemn the military action.
"For me, the commandment 'Thou shalt not kill' is unconditional," he told AFP at his house close to Kostroma.
He says few priests oppose the conflict because many are susceptible to "propaganda", combined with the fear of sanctions and prosecution.
Burdin, who teams his black cassock with a baseball cap and has a Telegram channel, says police have photographed his house and car.
Edelshtein says that Burdin is "braver than me, I am retired."
He did not face any state sanction for signing Burdin's letter and had already largely retired from the Church, while still allowed to hold services.
Edelshtein had a Jewish father while his mother was a Polish Catholic. He converted to Orthodoxy in 1955, hoping to escape the Soviet system.
Yet Church leaders were "lackeys of the Communist regime," he says, and "Satanist" Joseph Stalin revived the current Moscow Patriarchy.
The two priests do not present themselves as dissidents, however, and in the name of Church unity say they are not calling for believers to disobey the Patriarch.
"If a person commits a personal sin, he himself rebels (against God), not the whole Church with him," Burdin says.
His recent setbacks have hit him hard, nonetheless. In early April he withdrew from active service and is thinking about whether to stay in the Church.
The son of a priest, he was ordained in 2015 after a career in journalism.
"If I'm within the Church but censoring myself as I speak, if I'm silent about a sin being a sin, and about bloodshed being unacceptable, then I will just gradually, without noticing, stop being a pastor," he says.