When Peter was in prison, the church prayed ceaselessly. In the book of Acts, chapter 12, it is recorded that Peter was arrested and put in prison by King Herod. The church, upon hearing this news, gathered together and began to pray for him. While they were praying, an angel of the Lord appeared and freed Peter from his chains, and he was able to escape the prison. The story highlights the power of prayer and the importance of trusting in God even in difficult situations.