Numbers 35:21-23

American Standard Version

²¹ or in enmity smote him with his hand, so that he died; he that smote him shall surely be put to death; he is a murderer: the avenger of blood shall put the murderer to death, when he meeteth him.

²² But if he thrust him suddenly without enmity, or hurled upon him anything without lying in wait, ²³ or with any stone, whereby a man may die, seeing him not, and cast it upon him, so that he died, and he was not his enemy, neither sought his harm;