Ethics lesson:—

When a person performs a criminal act, that person is, in essence, declaring that he or she is breaking a covenant with the law-abiding members of the tribe. The point is to isolate the offender from law-abiding citizens so the offender cannot repeat the crime. At one time, ostracism or exile was the appropriate method of isolation. The offender is no longer part of the tribe. In modern times, prison takes the place of exile. If the offender repents, mends his or her ways, and demonstrates convincingly that he or she now accepts the covenant, they may be allowed to return to the tribe, but, of course, on probation. Certain crimes may be regarded as so severe or of such nature that it is best not to allow the offender's return. The point is the protection the rest of the members of the tribe from those who would perform criminal acts. The deterrent aspect comes from the awareness of the members of the tribe that if they commit criminal acts, they will cast out of the tribe (literally become "outcasts").

If a person is isolated and it is then found that he or she is not guilty of the criminal act of which they are accused, they can be returned to the tribe (with, one would hope, compensatory reparations).

If, however, the tribe's focus is on punishment or vengeance rather than the protection of the tribe and the person accused is executed instead of exiled, and if it is later found that that person is innocent, no such restoration and reparations are possible. The tribe has not only committed an injustice, it has murdered one of its own. Assuming that the tribe has agreed to allow those who administer justice in its behalf to take such drastic and irreversible actions, the entire tribe is guilty.

Prison sentence=exile or isolation of the offender for the protection of the tribe. If an error is found, it is reversible.
Execution=vengeance. If an error is found, it is not reversible.

Basic issue:—Is your interest the protection and welfare of society? Or do you want vengeance? They are two separate things.

Don Firth