Growing in Grace

J.C. Ryle

"When I speak of 'growth in grace', I do not for a moment mean that a believer's interest in Christ can grow.  I do not mean that he can grow in safety, acceptance with God, or security.  I do not mean that he can be ever more justified, more pardoned, more forgiven, more at peace with God, than he is the first moment that he believes...
"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 [is capable] 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 someone '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 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."

JC Ryle, Holiness Evangelical Press, 1976, p84f.  Orig. published 1877.

While one might misinterpret Ryle's latter sentences to mean that one's spiritual maturity is ultimately, a steady, linear, upward and onward progression (which - from our perspective - it is clearly not, cf Romans 7), nevertheless the burden of the importance of Christian growth and giving ourselves wholeheartedly towards the pursuit of increasing Christlikeness, is the message we desperately need to hear and heed. 
See also here.