Prison

The Torah enumerates and defines many forms of punishment for sinners and convicted offenders, from simple fines to flogging and even capital punishment. Yet nowhere does it suggest incarceration as a form of punishment.

This is because the purpose of existence is to establish a G-dly abode in this world, which is accomplished by utilizing our individual, divinely endowed strengths and talents in the service of G-d. With all other forms of punishment (except for the death penalty, which, in those cases warranted by Torah, is the only atonement the offender can obtain), the individual suffers the penalty, is cleansed of his sin, and is then restored to freedom where he is expected to resume a productive life in the making of a more G-dly world. As a prisoner, however, one is denied the freedom to fulfill one's Divinely ordained mission, and hence, his reason for living.

To allow one to live, and yet to deprive him of living, is inhumane.