...the better you will trust Him; the more you trust Him, the better you will love Him; the more you love Him, the better you will serve Him. This is God's way: you are not called to buy, but to beg; not to be strong in yourself, but in the grace that is in Christ Jesus... Remember the growth of a believer is not like a mushroom, but like an oak, which increases slowly indeed, but surely.
From one of John Newton's letters. Read the full thing here