Religious meditative and contemplative practices (RMCP) are commonly modified in healthcare as "concentration techniques" aimed at goals defined by psychotherapy. Such appropriation of RMCPs can redefine and even reinvent them to the degree that properties of these practices are separated from elements crucial to their religious and spiritual traditions. To distinguish specific variables from extraneous ones in research of the efficacy of these practices, a careful examination of RMCPs is crucial. This paper considers Christian contemplative practices and mindfulness-based techniques in two focused frameworks, early Christian monasticism and present-day Person-Centered Therapy. I demonstrate that the conditions of these two contexts are incompatible with each other in significant ways, most specifically in relation to: what is required of the individual in each context, who directs each context, the worldview of each context, and the overarching goals of each context. The conflicting conditions of these contexts illustrate noteworthy complications that Christian mental health clinicians must consider as they attempt to ethically integrate psychology and spirituality in their therapeutic work.