NOTE: This is one of those "I had an idea." I may be trampling on all sorts of theological toes, but it is an interesting idea.
The Bible says that there is no condemnation for those who belong to Christ Jesus. Those in Jesus has received his Spirit and they have new freedom from the power of sin.
Sinful nature cannot obey the Law. So, the Law cannot save. So, God, motivated by love, sent his Son, Jesus, who was able to do what the Law could not. And when Jesus died for us, God declared sin's control over us was broken.
Does this mean we will never, ever sin again? Probably not. Our nature is still imperfect. Our hearts is not pure. But without the breaking of sin's power, we have no hope of growth or improvement. Sin and selfishness would continue to rule our hearts. Now, they are ruled by the love of Christ.