What does Exodus 21:15 mean?

“One who strikes a man so that he dies shall surely be put to death,

but not if it is unintentional, but God allows it to happen: then I will appoint you a place where he shall flee.

If a man schemes and comes presumptuously on his neighbor to kill him, you shall take him from my altar, that he may die.

“Anyone who kidnaps someone and sells him, or if he is found in his hand, he shall surely be put to death.

“Anyone who curses his father or his mother shall surely be put to death.

“If men quarrel and one strikes the other with a stone, or with his fist, and he doesn’t die, but is confined to bed;