One of the greatest problems in the spiritual formation conversation has been the divorce between theology and spirituality. One modern thinker bemoans that our saints used to be theologians and our theologians used to be saints. We might add that our theologians used to be our pastors and song-writers, while now most disappear to the academy with little influence on church and ministry. What might be more disastrous than our theologians failing to speak meaningfully into the Christian life, is the fact that those who pick up this task are often theologically illiterate. Those who seek to form our understanding of life under God often do so through modes of reason that are not theologically informed. What happens, inevitably, is that we are offered secular accounts of human formation rather than a development of truly Spiritual formation (formation through the work of the Spirit of God).
Theology serves the discussion of spiritual formation by constantly calling it back to the Gospel and the work of God to redeem his creatures by sending his Son and Spirit. Theology seeks to think along the contours of the Gospel such that our reasoning about this life under God is distinctively Christian. What must not happen, but has, is the baptism of various secular accounts of human formation that are simply colored with Christian themes. Rather, the Gospel itself is the engine by which we understand Christian formation. Spiritual formation, at its heart, is not human formation, but formation by the Spirit of God. For Christians, therefore, theology and spirituality must not be seen as isolated disciplines, but, rather, are two necessary components of being faithful to the call of Christ.