In this world, since there has been writing, when someone dies unless they are pregnant, they kill themselves on purpose, or they die while asleep, they will respawn where they last slept, just like in Minecraft. People also don't age past the age of 25 years old.
When they die their body turns to dust and they appear back where they last took a nap, but no scars and if any brain damage happened then they will be healed of it. (Only their body respawns - not clothing nor anything they were carrying on them.)
The problem is that when someone dies they feel all the pain they have ever felt both physical and mental between the last time they died and when they died again, so murder is still a awful crime according to their beliefs. If a person kills on purpose someone who is asleep or is pregnant they also die that instant forever.
If they killed the person who killed someone else it might seem like a good idea, but they believe that whoever killed the murderer would also be a murderer and equally as guilty, so killing them for that crime isn't an option. What other ways could murderers be punished?
(This takes place in the 3000s and 4000s B.C.E. Wars would still be a thing because some tribes don't consider other tribes as equal. When I say tribe I mean a group of people, cities, kingdoms, or hunter-gatherer societies.)