Jerusalem, Isaiah charges, is full of “murderers.”  That is to say, it is like a city of refuge - the same word is used some 20 times in Number 35 to describe both the “manslayer” who finds refuge, and the murderer who is put to death.

Isaiah uses the image of a city of refuge ironically.  Cities of refuge were to be places of refuge from avenges; Jerusalem has become a place where violence is rampant.  Cities of refuge were to exclude murders and include only those guilty of accidental manslaughter; Jerusalem is populated by people who kill, preying in particular on the weak and helpless.