At the invitation of an atheist leader, Denis Bondarenko and Vitaly Fonichenko are on a mission from God.
Their destination is North Korea, the last Stalinist state on Earth, ruled by a government that bans free worship, and branded by President Bush as part of an "axis of evil."
Next year, the two trainee priests will open an Orthodox church in the North Korean capital, Pyongyang -- the first in the isolated country now at the center of an international row over its nuclear weapons program.
North Korea's unpredictable leader, Kim Jong-il, personally ordered its construction after a surprise visit to a church in Khabarovsk on a 2001 tour across Russia on his personal train.
He has now sent four North Korean academics to a Moscow seminary to train as Orthodox priests.
So why would the atheist leader of a country where all foreign influence is regarded with suspicion suddenly start to show interest in the Orthodox faith?
"God knows," said Dmitry Petrovsky from the church's external relations department with a slight smile. "Sometimes, God works in mysterious ways."
The church's aim, ostensibly, is to cater for the 300-400 Russians living and working in Pyongyang and perhaps a handful of North Korean followers of the Orthodox faith, he explained.
But this church is much more than a house of worship.
It is a symbol of a new relationship between the two former communist allies, who drifted apart after Moscow opened ties with South Korea in 1990 and then cut subsidies for the North after the Soviet Union's collapse a year later.
"It's a political gesture," said one Moscow-based diplomat. "The important things is that it opens up another channel of communication with Pyongyang."
Russia's President Vladimir Putin, an Orthodox believer with close ties to the church, has tried hard to rebuild relations with Pyongyang in the last few years, anxious to avert a nuclear or refugee crisis on Russia's far eastern border.
North Korea, which will pay for the church's construction, is also keen to revive the relationship with one of the few countries it can consider a friend.
Putin became the first Kremlin leader to visit North Korea in 2000 and Kim visited Moscow the following year.
But Galina Prozorova, author of a book on the history of the Orthodox church, says the church is not just about diplomacy.
"I think Kim knows there is not just an economic crisis in his country but a spiritual one," she said. "He also knows that Russian patriotism today is very closely linked to the church. Maybe he would like the same in his country."
Construction began in June after a ceremony to consecrate the church's foundation stone. Bells are being made at a factory near Moscow.
The two Russian student priests who volunteered to open the mission have been studying Korean for several months.
And the four North Koreans who will eventually take over from them began accelerated training for the priesthood in April at the Moscow Theological Seminary.
"They mostly concentrate on two things -- Russian language, including Church Slavonic, and the catechism to prepare for baptism," said Petrovsky.
"It's a really different way of life for them."
Religion is controlled by the state in North Korea and worship banned outside the official Korean Union of Believers.
The Orthodox Church has now been approved as an official religion, but proselytizing is strictly taboo. The priests' flock will consist largely of Russian embassy staff.
"Still," said Prozorova. "It's wonderful to think of those church bells ringing out over Pyongyang."