ABSTRACTCharismatic Christians in Ghana display heterogeneous intensities of personal piety, often mapped out by believers to levels of ‘spiritual maturation’. In this article, I examine the devotional routines of ‘committed’ Christians, individuals recognized as ‘prayerful’ subjects. Through Marcel Mauss’ incidental definition of prayer as an ‘expenditure of physical and moral energy’, I investigate ethnographically the methods whereby prayerfulness comes about. I argue that charismatic prayer is not a discernible object of inquiry, but an ongoing field of ethical problematization driven forward by two modes of physical and moral expenditure: habit and anticipation. From this angle, spiritual maturity indicates not a durable ethical asset, but a continuous effort to produce homeostatic balance between these embodied temporal forces. I conclude by stressing how attention to the internal goods of prayer allow us to integrate vulnerability within religious projects, instead of reducing it to an external causal force, as in most deprivation theories of religion.