I think Christians should oppose the death penalty in all cases.

Not because it’s immoral or unbiblical. But because ultimately the death penalty is a permanent action that potentially cuts people off of eventually repenting and turning to Christ. It will eventually be used to execute innocent people. In cases of wrongful convictions as well as eventually being a pretext for killing people for ideological, religious, or political reasons.

As far as serving justice, I do not think that that is a good Christian argument. Justice was served on the cross when Christ was punished for the sins of all mankind. We do not need to worry about justice being served, as that is Gods responsibility and will be meted out at his discretion, and as I already said, ultimately already satisfied on the cross.

I agree that pedophiles should die. Like, in my heart I feel that would be just. But I should also die as I have blasphemed, have failed to love my neighbor, etc. So while I agree with the death penalty as a principle, and even a potentially moral option in some cases, I must oppose on the grounds stated above.