For a while now I've been writing a book about kingdom journeys - the pilgrimages we go on to grow spiritually. I call them "kingdom journeys" because they build the kingdom of God. For whatever reason, it's not been an easy book to write. Maybe it's because I've got too much to say and can't cut it back enough. Or maybe I haven't learned enough about the subject yet.

It's my hypothesis that a kingdom journey is a kind of spiritual discipline. When they work as God intended them to, they lead us into hard places, places where we're uncomfortable. Places like abandon and brokenness.

We know about the spiritual disciplines of fasting, solitude and prayer, but what about the discipline of a spiritual journey? Jesus sent his disciples out on them. His three years of ministry was one big journey. And within that span of time, he launched them out on multiple other sub-journeys - practice runs where they could get ready for life after their rabbi was gone.

Discipline is a bad word for a lot of people. In a nation of parents who don't discipline their children, getting dessert before dinner has become normal.

Who likes spiritual disciplines? The author of Hebrews says, "No discipline seems pleasant at the time, but painful. Later on, however, it produces a harvest..." (Heb. 12:11) Spiritual disciplines involve self-denial, a postponement of pleasure for spiritual gain.

And in that regard, a short-term mission can be a kind of kingdom journey. When done well, that is, when they are long enough and challenging enough, following the precepts of Matthew 10, they take you to new physical places with spiritual parallels. You go on them to serve others, setting aside your own needs and wants. I've devoted my life to helping people grow as disciples through their journeys. Over and over again I've watched them radically transform people's lives.

It was the discipline of a kingdom journey that changed my life and has kept changing it over the years. Going to Indonesia for a year after college challenged me to think in new ways, meet new people, and cope with numerous physical challenges. It created the context in which I could grow spiritually.

My thinking about this is still taking shape. No doubt many of you reading this have been changed through your own kingdom journeys. If you've got insight along these lines, I'd appreciate it. What was it that helped change you? How was your experience like a discipline?