Biblical Penology

William Jenkyn, An Exposition Upon the Epistle of Jude, pp. 174-175:

The second branch of jurisdiction which belongs to the magistrate, consists in the distribution of rewards and punishments. 1. Of rewards to those who keep; 2. Of punishments to those who break the law.
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2. Of punishments. These are of sundry kinds. Some concern the name, as degradations; some the estate, as pecuniary mulcts; some the body, and these are either capital, or not capital, as mutilation of some part, &c. Evident it is from Scripture commands, that it is the magistrate's duty to punish: "The judges shall make diligent inquisition. And thine eye shall not pity, but life shall go for life," Deut. xix. 18, 21. (2.) From his function: "He beareth not the sword in vain," Rom. xiii. 4. (3.) From the benefit of these punishments. To the punished, who may grieve for what they have done; to the spectators, who may be warned from doing the same, Prov. xix. 25. Sinful indulgence silently, yet strongly, invites to a second wickedness. Even capital punishments are enjoined by Scripture: "Whoso sheddeth man's blood, by man shall his blood be shed," Gen. ix. 6; Exod. xxi. 12; Lev. xxiv. 17, &c.; a law which, being before the erection of the Mosaic polity, shows that the laws which afterward commanded capital punishments, did not simply and absolutely, but only, in respect of some circumstances, concern the Israelites. The capital punishment of malefactors by the magistrate was dictated by the law of nature. And as the force of the aforesaid command was before, so it continued after Moses; Christ himself, even from it, drawing an argument to dissuade Peter from shedding of blood, Matt. xxvi. 52. Nor do I understand but that, if all punishments of malefactors by the sword be now unlawful, that all defending of the subjects by the sword against an invading enemy is unlawful also; the public peace being opposed by the one as much as the other; nay, may we not argue, that if the power of the sword belong not to the magistrate to defend the commonwealth, that it belongs not to any private man to defend himself against the violent assaults of a murderer?

In sum, capital punishments may be inflicted, but sparingly, slowly. It is observed by some, that God was longer in destroying Jericho than in making the whole world. As many funerals disgrace a physician, so many executions dishonour a magistrate. The execution of justice should, like thunder, fear many, and hurt few: let all means be tried before the last be used. A magistrate must not be bloody when he sheds blood: the master bee alone is (they say) without a sting. If a butcher may not be of the jury, much less may he be a judge. In a doubtful case, it is better to spare many nocent than to punish one innocent; nor must vehement suspicion, but clear evidence, satisfy a judge. Punishment delayed may afterward be executed; but being once executed, cannot be recalled; and even when the malefactor is condemned, the man should be commiserated; though as an offender his blood be debased, yet as a man it is precious.