For rulers hold no terror for those who do right, but for those who do wrong. DoI could not help but think that Paul could not have been much more obtuse if it was truly his intention to endorse the death penalty. Most Christians don’t seem to believe that Proverbs 13 requires them to use an actual rod to whack their children. Why should they believe that Romans 13 requires a literal sword and literal bloodshed rather than seeing the sword as merely symbolic of the state’s right to punish criminals?
you want to be free from fear of the one in authority? Then do what is right and
he will commend you. For he is God's servant to do you good. But if you do
wrong, be afraid, for he does not bear the sword for nothing. He is God's
servant, an agent of wrath to bring punishment on the wrongdoer.
Jehovah was very big on killing people who displeased him in the Old Testament, but it seems to me that Christians who want to use this to justify the death penalty have to do a lot of cherry picking. For example, the Old Testament prescribes the death penalty for blasphemy, adultery, homosexuality, witchcraft, and disrespect for parents. Moreover, it prescribes stoning and burning as appropriate methods of capital punishment. I don't really see how the Old Testament can be used to establish the inherent morality of the death penalty without also accepting that it establishes the crimes to which it should be applied and the methods by which it should be carried out.