A Chinese church accountant who was imprisoned after being falsely accused of conducting "illegal business operations" has shared how her time in prison strengthened her faith.

Persecution watchdog China Aid reports authorities this week released Zhang Xiuhong, Huoshi Church's accountant and chairwoman of the board of deacons, after holding her in prison for more than two years on a falsified "illegal business operations" charge.

While in prison, Zhang penned a poem reflecting on God's faithfulness, which she shared with her cellmates.

Reads the poem, in part:

"This year, I was never in a dark place while waiting; the sun above the clouds shined upon me and nourished me;

This year, I was never homesick;

This year, I enjoyed the bounty of grace because my trust in the Lord who called me brought me unspeakable glory and joy;

This year, the world drifted farther away from me;

This year, my Lord drew ever closer to me;

This year, I received the fruits of the Lord's Holy Spirit: love, joy, peace, patience, kindness, goodness, gentleness, and self-control;

This year, I bathed in His love;

This year, my soul broke free from the metal bars of prison and soared in the Kingdom of God;

This year, I lived in hope and divine promises...."

Zhang was first taken into police custody in July of 2015 after she allegedly used a cash register in a beauty shop to withdraw church funds. The Christian woman''s house was later raided, her computers, USB drives and hard drives confiscated, and her husband taken into custody, leaving his 80-year-old mother and three-year-old adopted daughter alone in the house. He was released the next day.

However, government officials formally arrested Zhang a short time later, and tried her in January. According to reports, her interrogators' questions mainly focused on the church, its pastors and other core members, rather than her business activities.

Originally, she received a five-year sentence, but after she appealed, the court reduced it to three years' incarceration with a five-year probation.

Zhang's imprisonment comes as part of a wider crackdown on Christians in China. Officially, the country only allows the operation of churches legally registered with their local governments through the Protestant Three-Self Patriotic Movement or the Chinese Catholic Patriotic Association.

Thus, underground or unregistered house churches are illegal in China and are often subjected to raids and other forms of intimidation by the authorities. Some local governments in China have shut down these unregistered churches.

The country is ranked 39th on Open Door USA's World Watch List of countries where Christians face the most persecution.

Nevertheless, China is in the grip of "one of the world's great spiritual revivals" and an "explosion of faith" that shows no signs of slowing down, says a Pulitzer-prize winning author Ian Johnson.

"The decades of anti-religious campaigns that followed the 1949 communist takeover are giving way to a spiritual transformation-and among the fastest-growing drivers of that transformation are unregistered churches," the author of The Souls of China: The Return of Religion after Mao writes.

These unregistered churches, he says, have "become surprisingly well-organized, meeting very openly and often counting hundreds of congregants."

"They've helped the number of Protestants soar from about one million when the communists took power to at least 60 million today," he writes.