Hastings' Dictionary of the Bible (1898)
MUR'DER. The Jewish law calls a murderer one who slays another from enmity, hatred, or by lying in wait. Otherwise it is manslaughter, but the avenger of blood might kill the unintentional murderer if he overtook him before he reached the city of refuge. For intentional murder there was no pardon; the city of refuge, and even the altar, furnished no asylum, nor might money be taken in satisfaction. Ex 21:14, Ex 21:28-29; Num 35:30-32; 1 Kgs 2:5-6, 1 Kgs 2:28-34.
It was one of the most odious and abominable crimes, Deut 19:13; John 21:9; Num 35:33-34, and was a subject of early and severe legislation. Gen 9:6. See Cities of Refuge. A remarkable regulation made it legal to kill a housebreaker taken at night in the act, but murder if killed during the day. Ex 22:2-3. For the punishment of murder see Punishments.