When I speak of “growth in grace” I only mean increase in the degree, size, strength, vigour, and power of the graces which the Holy Spirit plants in a believer’s heart. I hold that every one of those graces admits of growth, progress, and increase. I hold that repentance, faith, hope, love, humility, zeal, courage, and the like, may be little or great, strong or weak, vigorous or feeble, and may vary greatly in the same man at different periods of his life. When I speak of a man “growing in grace,” I mean simply this,—that his sense of sin is becoming deeper, his faith stronger, his hope brighter, his love more extensive, his spiritual-mindedness more marked. He feels more of the power of godliness in his own heart. He manifests more of it in his life. He is going on from strength to strength, from faith to faith, and from grace to grace.
—J. C. Ryle
Holiness: Its Nature, Hindrances, Difficulties and Roots, 121–122.