Thou shalt not kill.

[180] We have now completed both the spiritual and the temporal government, that is, the divine and the paternal authority and obedience. But here now we go forth from our house among our neighbors to learn how we should live with one another, every one himself toward his neighbor. [181] Therefore God and government are not included in this commandment, nor is the power to kill, which they have, taken away. For God has delegated His authority to punish evil-doers to the government instead of parents, who aforetime (as we read in Moses) were required to bring their own children to judgment and sentence them to death. Therefore, what is here forbidden is forbidden to the individual in his relation to any one else, and not to the government. ...