The Liberty of Obedience

In the final chapter of the book, spiritual maturity is discussed. After looking at the true definition of "sin" and our response to it in the beginning of the book, it ends with a word of hope for us...the hope of maturity and also conformity to Christ......

"He (God) wants us to reach maturity. He has so arranged things that if we are to go on beyond the 'milk diet' we shall be forced to think. We must train our faculties by practice to distinguish between good and evil. We are fond of quoting Romans 8:28. But this verse is nearly meaningless without its following verse, in which lies another definition of maturity. 'to be shaped to the likeness of his son' (N.E.B.). Unless we see this as the true 'good' referred to in verse 28, we shall wonder how Paul can possibly have been so naive. We shall be forced to regard him - perhaps with affection and certainty with pity - as a misguided Pollyanna, trying to prove to himself that there is always something to be glad about, and shutting his eyes to the sad and the bad. But, given the definition of verse 29, we see that all our spiritual education is directed toward god's idea of good, this 'conformity to Christ'.
Note that He is not interested in conformity to a static code but to a person, the 'likeness of His Son,' the living expression of Himself, the very Life of all the ages. This is a far cry from a stereotype. Had God given us a minute prescription for our behavior, no high development of individual character would have been necessary to meet it. He need not have mentioned discernment. But the Law, said the writer to the Hebrews, was incapable of bringing anyone to maturity. The 'letter' - for example, a rule book, a code, a policy - is deadening. It cannot stimulate growth.
..But no policy can encompass in advance the difficult paths through which God may lead a soul to maturity. The man who determines to go on to perfection must go on alone. The child must learn independence. James wrote that when endurance is fully developed 'you will find you have become men of mature character with the right sort of independence' (james 1:4, Phillips translation)...
....Maturity was Paul's goal for others as well. 'We warn everyone we meet, and we teach everyone we can, all that we know about him, so that, if possible, we may bring every man up to his full maturity in Christ Jesus. This is what I am working at all the time, with all the strength that God gives me' (Col 1:28, Phillips)."