The Ligonier Blog recently answered the question:
"How can I prevent my personal Christian growth from becoming stagnant?"
Here's a short quote from it:
"Obviously our Christian growth can move at various speeds, and we tend to have a kind of ebb and flow. Sometimes we’re moving ahead in leaps and bounds and other times at a snail’s pace. When it’s moving in such a laboriously slow fashion, we may think that it has become utterly stagnant. Again, if there is no evidence of growth whatsoever then I would say it’s time to examine our souls and our hearts to see if we’re in Christ at all because where the spirit of Christ indwells a person, he will not permit total stagnation."
Read the whole post
Also of interest may be 'Deeper into the Gospel' a quote at 'Of First Importance'.