Joshua 20:3 That the slayer that killeth any person unawares and unwittingly may flee thither: and they shall be your refuge from the avenger of blood.
God’s Word shows us how He taught His people such good things and well before it had been developed by others. Here is a good example. The Jewish legal system understood involuntary man slaughter and had a separate penalty for it. A person might kill by accident. The victim was still dead so God taught His people to have that person be allowed to live but confined for a certain length of time.
When you hear people criticize the Bible you might should ask what their motives are. Have they read the Bible? Do they just have a hatred for God that causes them to malign the Bible? It is a most wonderful book that should be considered awesome, awe striking to you! I never read it without being impressed with the wisdom God gave His people!