I am not totally sure about what I'm going to write, but for me, it seems to be true.
I think one of God's means of discipline is allowing His child to have sin in his or her life (obviously, seeing as nobody is sinless). Sometimes I wonder why God doesn't just change me overnight. I'm sure all Christians wonder why we can't change and do the same things over and over. So we come to the conclusion, "I've got to try harder!"
Again, don't take my word for it, but I think God may allow sin in my own life because it keeps me in grace and allows me to be well established in grace. This is what I mean by grace hurting. To be deeply rooted in grace, means stretching your faith and letting go of the faithlessness of self-righteousness. This is scary and it gets hard sometimes. We know how much God hates sin, and want to overcome it. But perhaps He allows you to have it so you recognize your brokenness. Perhaps He is changing the reason for your desire of increasing in holiness.
If God were to change me overnight, freeing me from timidity, anger, selfishness, and so on, then I would have a bigger problem - Pride. I would drift right back into law and come boldly to the throne of GRACE with my own soiled garments of self-righteousness.
It is one thing to say "His grace is sufficient", but taking the leap of faith to apply that can be painful. It forces you to be honest with your indwelling sin, rather than covering it up with good works, good behavior or re-dedication, which is bondage.
I love how Rob Rufus put it in one sermon. He said he once prayed for God to reveal all his faults so he could fix them. He felt God say, "Son, if I did that, you would want to kill yourself."
Why? Because it would completely overwhelm him. I don't think anyone has the capacity to have that kind of faith.
I noticed, while living under law and shoulds, that I became increasingly aware of my faults. I thought it was because God wanted me to change thus and so about my life. But as I would try and juggle these areas of my life, I would eventually lose rhythm and everything would fall apart (not that I ever had it together).
God was indeed putting more on me than I could bear. The overwhelming feelings of unworthiness and constant condemnation was God driving me to faith.
"What man, desiring to build a tower, does not first sit down and count the cost?"
I realized Jesus wasn't asking me to pay it, but showing me I couldn't. Now it's a daily acknowledgment of that. Every day I try to sink deeper and deeper into Christ and knowing nothing but Him crucified. You could say I take up my cross daily and deny myself. My endeavor is to count all things I thought were gain, as loss for the sake of knowing Christ.
"Whoever would save his life will lose it".