Christians who have experienced persecution and suffering firsthand for their faith have asked people in the free world to keep praying for their brothers and sisters in prison.
Susanna Koh, the wife of abducted Malaysian pastor Raymond Koh, said she had often used the Psalms and other passages of Scripture to express "feelings of anger, loss, of grief, especially when words fail me and sometimes we don't even know how to pray."
"Prayer is a cry from the depths of our hearts," she said.
Her husband was abducted from his car in 2017 and has not been seen or heard from since. Malaysia's Human Rights Commission concluded that state agents were involved in his kidnapping.
"It has been a long and difficult journey for the family and it is only by God's grace and the prayers of Christians worldwide that we can stand strong in the midst of the storms of life," she said.
Susanna told of how prayer helped her when she was taken to the police for interrogation: "Fear gripped my heart. I cried out to God, 'Lord help me.'
"Immediately the fear disappeared and a song, 'I raise a hallelujah', came out of my heart. The Holy Spirit gave me boldness and I exerted my right and asked for my lawyer to be with me.
"Prayer of the saints is like incense rising up to Heaven. When Christians pray, God is pleased and He is glorified and honoured.
"Prayer unites us as a body of Christ. As we pray for one another, we draw closer to each other, we suffer with those who suffer, we weep with those who weep. May God's name be exalted and magnified through His children."
The live event also heared from Czech aid worker Petr Jasek, who said his prayer life was "deepened" by his experience of being imprisoned by ISIS in Sudan.
"Prayer was my only source of strength," he said.
He recalled how the ISIS fighters would have a lot of "noisy fun" late into the night, and sometimes through to the morning. Yet every night, he was able to sleep peacefully.
When he was allowed to receive letters from family three months into his captivity, he discovered that his church had started a prayer and fasting chain, and that they were praying at exactly the time he was going to sleep for the night.
"Thanks to their fervent prayers, I was able to sleep peacefully amidst the enemies of the Gospel," he said.
"When I found out about the reason for my sleep I was convicted by the Holy Spirit: how many times someone asked me to pray for him or her and I just responded with the typical Christian social phrase 'yes, yes, I will keep you in my prayers', but maybe I only prayed once or twice but then I was done.
"Now that I was in prison, I understood the importance of keeping this commitment to pray. Therefore I immediately started to pray for other imprisoned believers in many restricted countries."
Jasek has followed that commitment through and continues to encourage those living in freedom to pray for Christians living under oppression.
"We serve an omnipotent, omnipresent and omniscient God who alone can help the persecuted brothers and sisters. However, he wants to hear from us and answer our prayers," he said.
Helen Berhane, who was locked up and tortured in a shipping container in the Eritrean desert for two years, also had a powerful testimony to share.
She spoke of how the shipping container would be so hot during the day that it would burn her skin, only to become so cold after sundown that she was shivering through the night.
She said it was remembering Paul and Silas singing in prison that gave her encouragement.
"The guards tried to stop me but I kept singing and kept preaching the Good News to anyone who would listen," she said.
When she refused to stop, they tortured her.
"Their goal was for me to deny my faith: 'Stop saying "Jesus".' All I could answer was: 'I cannot, I accept Him unto death.'
"But your prayers carried me through," she continued.
"I would tell the other prisoners, 'People are praying for us, I can feel it.'"
She ended with an appeal to Christians in the free world to pray for persecuted believers.
"The name of Jesus is medicine and the world desperately needs it. Our brothers and sisters are still in prison. While we eat, they have no food. While we are free, they are in chains.
"We can do more. Keep on praying, keep on supporting, keep on singing."