To die the death is death to self and the sword in revelation is the word of God.
Let me ask you something, could you do it? Could you be the one to use the knife or shoot the gun?
What would you do if saying you believe in capital punishment, you say yes to killing someone, or do it yourself and then find out they were innocent?
Would you worry incase the person you are condemning are ignorant? What if they have never heard the word of God before being killed, maybe when they heard the truth they would have been healed and there hearts changed. We don't know what suffering others have been through in their lives and many don't know God.
I don't know individual situations and circumstances, but there is also life imprisonment, and I know in my heart is wrong to murder and it's a work of the flesh. In either way, whether a person is a murderer or whether we murder for revenge. You say we are to obey Gods laws, and I agree as they should be in our hearts and in our minds. So the the law stands " thou shalt not kill" and I see the Bible differently to many here, I see it as the spiritual word of God written by those in the spirit.
And again Jesus said
Matthew 5
Ye have heard that it hath been said, An eye for an eye, and a tooth for a tooth: But I say unto you, That ye resist not evil: but whosoever shall smite thee on thy right cheek, turn to him the other also.
And again
Ye have heard that it hath been said, Thou shalt love thy neighbour, and hate thine enemy. But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you; That ye may be the children of your Father which is in heaven: for he maketh his sun to rise on the evil and on the good, and sendeth rain on the just and on the unjust. For if ye love them which love you, what reward have ye? do not even the publicans the same? And if ye salute your brethren only, what do ye more than others? do not even the publicans so?*Be ye therefore perfect, even as your Father which is in heaven is perfect.