As Americans gather to pray this Sunday during the International Day of Prayer for the Persecuted Church (IDOP), they should remember Christians in the world's most persecuted country.

Rev Eric Foley, chief executive of Seoul USA, says instead of praying for members of the North Korean underground church, Americans should pray with them.

"They don't ask God to deliver them from persecution. They pray they'll remain strong and faithful in the midst of their suffering," he said.

Foley says Americans may be surprised to learn that North Korean Christians often pray for people of the USA and South Korea.

"They pray for us because they feel we are persecuted by our prosperity and it distances us from God. They pray that we will remain faithful to the Lord."

Seoul USA recently obtained exclusive new video of faithful North Korean Christians worshipping inside a North Korean home. The rare, amazing video may appear shocking because the underground Christians shown are not poor. "It means the gospel is spreading among those in the higher classes," says Foley.

And China has recently joined NK government efforts to prevent the gospel from spreading inside North Korea by jamming Seoul USA's Christian shortwave radio broadcasts.

"The co-opting of the Chinese government suggests the North Korean regime feels threatened by these broadcasts," says Foley.

The North Korean government has tried repeatedly to extirpate Christianity from the country, but the underground church has survived and has overcome severe suffering.

"The NK Christian's example may help Americans better prepare for the persecution that may be coming soon to the USA," explains Foley.

"Their experience reminds us that a commitment to the four pillars of worship is integral to the Christian life."

The four pillars are featured in Seoul USA's 100 Days of Worship campaign that runs through December 31.