"A number of Americans were captured in Vietnam. They then decided to write a Bible for themselves in prison from memory. Each person quoted verses he knew from the Bible. It started off with a flourish. One after another they quoted Bible verses, as one wrote them down on a piece of paper.
Too soon they realized how limited their Bible knoweldge was. Except for John 3:16, Psalm 23, the 'out father' and the 'ten commandments', they could remember only a few more verses. They stared at one another dejectedly; in an hour they had perhaps twenty verses. They kept on trying, only to discover that they were confusing one verse with another.
It was obvious. The word of God did not dwell in them richly. No matter how hard they tried, they could not quote any more verses correctly. 'Let the word of Christ dwell in you richly. (Colossians 3:16).'
The Bible is a banned book in times of persecution. In China, Laos and Vietnam, the Communists either burned or confiscated thousands of Bibles. When the Christians assembled, they could do little more than the American prisoners of war. They tried to quote the Bible but did not get very far. The reason was simple. While they lived in freedom they had not seen the need for Bible memorization. Why exert yourself by learning Bible texts if you have a Bible on your bookshelf?
When the Christians saw the necessity of Bible memorization, it was too late. One cannot attempt to learn bible verses once the Bibles have been confiscated or burned. It takes time and it must start while there is still freedom."
- Jan Pit, from "Persecution: It will never happen here?"