Reason, in the classical and Christian sense, is a whole way of life, not the simple and narrow mastery of certain techniques of martial manipulation, and certainly not the childish certitude that such mastery proves that only material realities exist. A rational life is one that integrates knowledge into large choreography of virtue, imagination, patience, prudence, humility and restraint. Reason is not only knowledge, but knowledge perfected in wisdom.
In Christian tradition, reason was praised as a high and precious thing, principally because it belonged intrinsically to the dignity of beings created in the divine image; and, this being so, it was assumed that reason is also always morality, and that charity is required for any mind to be fully rational. Even if one does not believe any of this, however, a rational life involves at least the ability to grasp what it is one does not know, and to recognize that what one does know may not be the only kind of genuine knowledge there is.
-David Bentley Hart, from Atheist Delusions