The Devil looks after his own.

We all know the person who seems to break all the rules and get away with it. Perhaps they do, perhaps they don't, but perception is sometimes more potent than reality. This saying dates from the time when people had strong religious convictions and they were puzzled as to why some people appeared to get away with wrongdoing - hence the put-down of the Devil looking after them on Earth but hinting that they would get their comeuppance in Hell.