Walter Hilton in The Scale of Perfection (1.14):
There is many a man that has virtues, such as lowliness, patience, charity towards his fellow Christians and so on, only in his reason and will, but without any spiritual delight or love in them. Often he feels grudging, sad and bitter as he practices them, and nevertheless he does it, stirred only by reason and the fear of God. This man has virtues in his reason and will, but not love of them in affection. But when by the grace of Jesus and by spiritual and bodily exercise the reason is turned into light and the will into love, then he has virtues in affection, for he has so well gnawed the bitter bark of the nut that he has broken it and feeds upon the kernel.