The Faith of a Christian
Many people view the Christian faith as something easy, and some even place it among the virtues. They do this because they have not experienced faith, nor have they tasted its great power. A person must experience the strength faith provides in the midst of trials and misfortune. Otherwise, it is not possible to write well about faith or to understand what has been written about it. But one who has had even a small taste of faith can never write, speak, reflect, or hear enough concerning it. As Christ says, it is a "spring of water welling up to eternal life" (John 4:14).
-Martin Luther, The Freedom of a Christian