John Calvin, on Christian religion:
For [the Christian gospel] is a doctrine not of the tongue but of life. It is not apprehended by the understanding and memory alone, as other disciplines are, but it is received only when it possesses the whole soul, and finds a seat and resting place in the inmost affection of the heart.
Accordingly, either let them cease to boast of what they are not, in contempt of God; or let them show themselves disciples not unworthy of Christ their teacher.
We have given the first place to the doctrine in which our religion is contained, since our salvation begins with it. But it must enter our heart and pass into our daily living, and so transform us into itself that it may not be unfruitful for us.
The philosophers rightly burn with anger against, and reproachfully drive from their flock, those who when they profess an art that ought to be the mistress of life, turn it into sophistical chatter. With how much better reason, then, shall we detest these trifling Sophists who are content to roll the gospel on the tips of their tongues when its efficacy ought to penetrate the inmost affections of the heart, take its seat in the soul, and affect the whole man a hundred times more deeply than the cold exhortations of the philosophers! (Institutes of the Christian Religion 3.6.4 [p. 688])