When I was in the third or fourth grade, a foreign missionary who had been imprisoned in communist China for years, gave a talk at my elementary school. I was pretty young, and my attention span fairly short, but a few things stand out in my memory. She said the first thing they did before locking her up was to take her Bible. They had no idea what it was really about, but they knew it meant something to the missionaries, so they took it away.
She said the cell she was in was so small she could go from wall to wall in just a few steps, and that pacing back and forth was the only exercise she could get. After a year or so of that, she said she felt as if she was losing her sanity. She said 3 things saved it: faith, fervent prayer, and reciting Bible verses she knew by heart. These things could not be taken from her, and they carried her through her ordeal. I've wondered over the years, how well I would deal with her situation, if my faith called for it. I know that, like her, I would draw my strength on faith, sweet communion with God, and memorized passages of Scripture. Two of the first verses I committed to memory as a new Christian were these:
Trust in the LORD with all your heart; and lean not to your own understanding. In all your ways acknowledge him, and he shall direct your paths.
I am crucified with Christ: nevertheless I live; yet not I, but Christ liveth in me: and the life which I now live in the flesh I live by the faith of the Son of God, who loved me, and gave himself for me.