This is one of my favorite passages in Calvin’s writings.
Doctrine is not an affair of the tongue, but of the life; is not apprehended by the intellect and memory merely, like other branches of learning; but is received only when it possesses the whole soul, and finds its seat and habitation in the inmost recesses of the heart …. To doctrine in which our religion is contained we have given the first place, since by it our salvation commences; but it must be transfused into the breast, and pass into the conduct, and so transform us into itself, as not to prove unfruitful. If philosophers are justly offended, and banish from their company with disgrace those who, while professing an art which ought to be the mistress of their conduct, convert it into mere loquacious sophistry, with how much better reason shall we detest those flimsy sophists who are contented to let the Gospel play upon their lips, when, from its efficacy, it ought to penetrate the inmost affections of the heart, fix its seat in the soul, and pervade the whole man a hundred times more than the frigid discourses of philosophers?
Institutes III, vi, 4.