The biblical concept of the image of God lay at the heart of abhorrence to the taking of a human life. However the idea of a divine image was understood—physical likeness, self‐transcendence, capacity to communicate, authoritative rule—it implied that one dare not destroy another person who bore God's image. The story of the first murder, Cain's slaying of his brother Abel, insists that spilt blood cries out to the creator, who acts to ensure vindication but not at the expense of compassion (Gen. 4.8–16). This tension between revenge and mercy produced responses to murder that lack consistency precisely because they take mitigating circumstances into consideration.

The Ten Commandments prohibit murder categorically (Exod. 20.13; Deut. 5.17) and without exception. Nevertheless, in Israel's day‐to‐day existence distinctions were made, and killing was held to be justified in at least two situations, warfare and execution for capital offenses. The first of these was fortified by the conviction that Israelites engaged in holy wars, with Yahweh as their commander‐in‐chief. In these circumstances compassion had no place, particularly when the enemy was placed under ḥērem (the ban). Saul's sparing of the Amalekite king Agag, whatever its motive, was deemed an act of disobedience, and the prophet Samuel carried out Yahweh's execution of Agag (1 Sam. 15.33). Israel's recorders of sacred history did not balk at depicting Yahweh as sanctioning, even ordering, such action. Elijah's slaughter of competing prophets raised no objections that were rooted in the Ten Commandments (1 Kings 18.40). The same leniency occurs with respect to cases of capital punishment. In fact, the blessing of Noah actually contains a stipulation that murderers are to be executed (Gen. 9.6).

The practical implementing of this sentence resulted in elaborate rituals and numerous distinctions. Premeditated violence differed from an act in the heat of anger or from accidental injury. From early times an institution, the avenger of blood (gōʾēl), assured vindication within each family. The next of kin assumed responsibility for avenging a death, and society sanctioned this means of obtaining revenge for grievous wrong. In time, ransom of the guilty person's life introduced the principle of monetary compensation for the loss.

In cases of accidental homicide, provision was made for the establishment of cities of refuge, thus enabling society to combine revenge and mercy (Num. 35.9–34). Persons who accidentally caused a death or who killed another person in a fit of anger could flee to a city of refuge and, after satisfactorily convincing officials that asylum was appropriate, entered the city and remained there until the high priest's death; thereafter the individual could return home without harm. Of course, these institutions of a redeemer and of cities of refuge sometimes failed, for not everyone respected the laws governing both.

In cases in which a murder occurred but the murderer was not known, the nearest town had a special ritual by which the people were exonerated of collective guilt (Deut. 21.1–9). The problem of adjudicating responsibility for murder was no simple matter. If an owner of a dangerous ox had been warned because of its habitual goring but failed to keep the ox under control so that it killed someone, the owner was held responsible for the death (Exod 21.29). Similarly, if two persons fought and one was injured but was later able to get up and walk around, the offender could go free even though death occurred a short time later (Exod. 21.18). Owners of slaves were not culpable if they beat them to death, provided that a day or so lapsed between beating and death (Exod. 21.20–21). Moreover, a person who killed a thief in the night was not held responsible for the action (Exod. 22.2).

The older institution of blood revenge gradually disappeared. By Ezra's time officials of the state handled such matters. The Romans seem to have restricted Jewish authority in case of capital punishment, and by insisting that the murderer had to be warned immediately before the crime, the rabbis made it virtually impossible to take human life. Jesus broadened the prohibition of murder to include anger (Matt. 5.21–22).

James L. Crenshaw