The Bible never speaks of “spiritual,” doesn’t even have a word for “spiritual,” and never uses the phrase “spiritual life,” thus indicating that all growth is spiritual (see Rob Bell’s “everthing is spiritual”). Physical growth is spiritual. How I pay my taxes is spiritual. For sure (as indicated by the number of times Jesus speaks about it) how we handle our money/possessions is spiritual. How i treat my neighbor is spiritual. Everything is spiritual.
I say this because is the church world we tend to hold “spiritual growth” up as the crowning form of growth. It seems that – in typical American Christian settings – it is great if you get into shape, but it is much better if you are a good, church member. We hold that up as higher. This is the beginning of a heresy that Paul was confronting: gnosticism. The view that God is only spirit and that all flesh is bad and that only the spirit is good.
That being said, I’ve experience (and my reading has backed me up) that people grow within relationship. The Good News is that we can be reconciled with God and with one another.
Richard Dunn writes that “trust produces relationship. Relationship conceives spiritual life exchanges. Such exchanges are the sacred places where the Holy Spirit reaches through the life of a Christian spiritual caregiver to change forever the life of a student.”