12 He that smiteth a man, so that he die, shall be surely put to death.

13 And if a man lie not in wait, but God deliver him into his hand; then I will appoint thee a place whither he shall flee.

14 But if a man come presumptuously upon his neighbour, to slay him with guile; thou shalt take him from mine altar, that he may die.

We now transition to laws of murder and capital punishment. Verses thirteen and fourteen makes a clear distinction between manslaughter and murder. The description of a man not lying in wait, but having another delivered into his hand by God, is generally understood to mean killing another by happenstance, not by malice aforethought.

We will read later how a man guilty of manslaughter could still legally be executed, but there were certain cities of refuge he could retreat to where it would be illegal to kill him. Thus, he was a man with a foot in two worlds, not entirely guilty but not entirely innocent, and the law was designed to reflect that nuance. But if the man was guilty of premeditated murder, not manslaughter, then there was no question what his outcome would be, the Lord commanded that such a man should be put to death.

This covers two of the most common forms of killing, but not all. What about killing another man in self defense? Verses 18-19 of this chapter, and also verses 2-3 of the next chapter, will give some more details on lawful and unlawful killing, but nothing concrete on self-defense. From the verses in the next chapter it seems like a man might have been justified in slaying an intruder who came into his abode during the dark of knight (when murderous intent was more likely), but not during the day (when thievery was more likely).