Recently, I have been taking my dog out in the early hours of the morning, just before sunrise. Dark enough that no one's around, light enough that it's easy to detect exceptions to the rule.
In the noisier times during the day, he doesn't get let off the lead much, lest he fight another dog, or run far enough away that I could not catch him. There is also an area near the road I never used to let him off, because he would always run towards it. However, with it being so quiet in the morning, I can afford to give him a little more freedom.
One thing I've noticed is that where he used to be very reckless, he has now learned to follow me. It's almost as if I hadn't taken him off the lead. He even follows me closer when we're by the road. And when I call him, he no longer ignores me, he comes straight to me. Put simply, from his time spent on the lead, he learned how to behave off the lead.
The law works much the same way. Human beings were never especially great at conducting ourselves. You only need to read Genesis to see that even the Godly people did things that even our depraved culture would consider, at the very least, rather odd. But now, having the full revelation of scripture, we understand God's heart clearly enough to be released from the law of Moses. As Paul said, the law was our "guardian" (HCSB), "schoolmaster" (KJV), "tutor" (NKJV).
The word carries a sense of a child minder. Someone whose job it was to not only protect, but also educate the child while the parents did other things. How many adults do you know who are followed by such people? Their job is to prepare the child for adulthood, and once they reach that, the job is done. So it is with the law of Moses. Israel was forced to be Godly until they, and the whole world through them, could learn to be Godly by our very nature.