My friend Dave Wilson relayed the story that he was stopped at an intersection behind a car and a motorcyclist. The motorcycle had fallen over sideways as it had rained and the road was slick. The guy was having a difficult time getting the motorcycle back right because the road was slick and it just slid over when he tried to right it.
On top of this, the guy just behind him was sitting in his car, mad, and honking. Finally Dave got out, walked over, and helped the guy pull his motorcycle back up, and away everyone went.
This is a perfect metaphor for law and grace. Yes, it is a problem to be down on your cycle stopping traffic. The law has power only to sit and honk - to tell you that you're wrong, to condemn. It has no power to help. Grace gets out, without judgement, and helps you get on your way, without anger or criticism.