Russian Orthodox Patriarch Kirill, a powerful ally of Russian President Vladimir Putin, is embracing the rhetoric of the mediaeval crusades in urging support for Moscow's offensive in eastern Ukraine.
Kirill has called on believers to support pro-Russian "brothers" during Moscow's offensive in eastern Ukraine, and in a sermon in September, he said that dying in Ukraine "washes away all sins".
As humiliating military setbacks for Russia in Ukraine pile up, authorities in Moscow seem increasingly willing to depict the campaign in religious terms.
Keen to ensure public support, Putin declared during his midnight address on New Year's Eve that "moral, historical rightness is on our side".
He had initially said that the fellow Orthodox Christian nation needed to be "demilitarised" and "de-Nazified".
But more than 10 months into Moscow's offensive, Russian authorities, military commanders and propagandists aim to depict the conflict as a battle against the decadent West.
In early November, former president Dmitry Medvedev said that Russia faced an existential threat and that the "sacred goal" was to fight the satanic West.
"We are listening to the words of the Creator in our hearts and obeying them," Medvedev, who serves as deputy chairman of Russia's Security Council, wrote on messaging app Telegram.
"The goal is to stop the supreme ruler of Hell, whatever name he uses —- Satan, Lucifer or Iblis."
Dozens of Orthodox priests have been sent to the front to support Russian troops.
The offensive has deepened a rift between the Russian and Ukrainian Orthodox churches. But even in Russia, not every cleric supports the rhetoric of the Moscow patriarchate.
The words come straight from the Middle Ages, said Andrei Kordochkin, an Orthodox priest based in Madrid, Spain.
"We can be nostalgic for the Middle Ages, but it is impossible to return there," he added. "War as a form of murder cannot have any spiritual meaning at all."
Kordochkin was among almost 300 Russian Orthodox clerics who signed an open letter urging authorities to end the "fratricidal war" in Ukraine.
"Many more" people agreed with the letter's message but were unable to sign it for various reasons, he said.
"We bitterly think about the chasm that our children and grandchildren in Russia and Ukraine will have to overcome in order to start being friends with each other again, respect and love each other," the petition said.
Several signatories of the letter have been sanctioned by the patriarchy, said one priest, requesting anonymity to speak candidly.
Some of the clerics were moved to other parishes and replaced by priests loyal to the Kremlin, he said.
"One priest served 30 years in his parish and was then transferred to serve elsewhere," he added, calling the Russian offensive a "catastrophe".