Why Do Civilizations have Laws?

in order for you to have a civilization you have to be civilized and if you define to be civilize it means to change the ways of (primitive people) to those found in a more advanced type of society and to have an advanced society you have to enforce rules

If a son strikes his father his hand shall be cut off. I said i was in the middle because if it was a tiny hit and they cut of his hand thats inhumane but if he was really physically abusing him they should punish him so he doesnt get spoilt but not something as barbaric as cutting off someones arm and plus he won't be off any use