"Thou shalt not kill," does not mean what it says. The Sixth Commandment should not be one's default argument when opposing doctor-assisted suicide, euthanasia, abortion and capital punishment, or when advocating pacifism and vegetarianism. The 1611 King James Version of Exodus 20:13, which says, "Thou Shalt Not Kill," is an inaccurate translation. That translation is too comprehensive for the language originally used. The term "kill" means to put to death and such a prohibition would condemn the taking of any life, human or animal. This Sixth commandment was never intended as a complete moratorium on "putting to death" or on "putting a human to death." When the Ten Commandments were first scribed in Hebrew, of two possible verbs, one was selected that best expressed the proscription against the unjustified taking of an innocent human life, which is murder. "You shall not murder." In seventeenth century England, when the KJV was translated, the words 'kill' and 'murder' were used synonymously. Since then, most translations have adjusted to the linguistic and historical reality, that the Commandment was a prohibition against murder. Appreciative of that distinction, an effective debater is compelled to deliver unambiguous, reasoned argument that this commandment against murder pertains to abortion or doctor-assisted suicide or capital punishment. I am not saying that this cannot be done, but that the use of the Sixth commandment as support must be unmistakably understood. That begs the question "What is murder?"
I have already proposed that it is the unjustified physical act of taking an innocent human life. "You shall not murder." Assess the following cases using that definition. A family must decide whether to remove a loved one from life support, knowing that the patient's body cannot survive apart from that intervention and that with the family's permission, the patient's heart will stop beating. The sniper is involved in a fire-fight and pops off enemy gunners one after another. Then in entering a local home, he confronts a family of seven, five of them children, kills them all, because they may be enemy sympathizers. Aerial assaults by Coalition forces light up an urban target with 'collateral damage' to civilians who lie lifeless in the street. A homeowner wakes up to an intruder, seizes a heavy object and pounds the trespasser to death. A woman drinks wine at a dinner, and later drives home and loses control of her vehicle, striking and killing an elderly couple as they cross the road. It is exceptionally challenging to examine the degrees of blameworthiness, yet the terms 'unjustified' and 'innocent' inform us that we must be discerning about the nuances.
Further, as I have stated, this Sixth commandment was not a complete moratorium on "putting a human to death." Capital punishment and military defense that takes life, is not automatically censured by this commandment. As unpalatable as it sounds, not all killing is murder. Of the two Hebrew words, transliterated as ratsakh and mut, the first, "לֹ֥֖א תִּֿרְצָֽ֖ח׃," meaning "murder" and other meaning "put to death," the first is never used in scripture with reference to war or to punishment of a murderer. It may be appropriate to say then, not all killing is wrong. God created humankind in his own image and according to his likeness, that is, possessing certain capacities that distinguish the species from all other creatures. This speaks to the sanctity of human life. Notably, the Biblical account of creation portrays earliest humanity aware of God, at peace with God and at peace with one another for only a brief time. Within the first family, antagonism arose early and one brother's life was taken by another. When considering blameworthiness and culpability, this story demonstrates the fragility of some judgments. The offending brother was not put to death but was sent away, suggesting that the offence was not regarded as "murder," but rather as a death incurred through violence fueled by anger and jealousy and pride. God made that distinction. Similar distinction was in evidence among Hebrews when God made provision for unintentional manslayers (manslaughter), to be able to flee to cities of refuge, where they could remain alive, not pursued or arrested but far from their families, which was their punishment.
This is a comment on social justice using the scripture as the primary resource. Consequently, referring to bad behaviour as "sin," is both understandable and suitable. God saw that humanity had become sinful and evil, "lawless" one might say, so he legislated these guidelines - commandments to modify human behaviour. There are two Greek words as well (phoneuo, apokteino) that mean respectively, “murder” and “killing,” and are used in the New Testament. Since not all killing is wrong, but all murder is wrong, scripture acknowledges the right of the state (government) to take the life of the evildoer, i.e. capital punishment. Killing that is done during times of war and is done at the command of superiors is not regarded in scripture as 'murder.' Therefore, like it or not, there are exemptions for taking a human life, as long as it complies with God's law and will.
As morally exhausting as this is, when Jesus was here, his teaching aimed at revealing the true intention for life in God's kingdom. We might all agree that murder is the unjustified taking of an innocent human life, only to be floored by higher New Testament standard. Of course God condemns the observable physical act of murder, yet the entire truth is that God can look into the human heart to see something there that he regards as murder. Any thought or feeling of deep-seated hatred or malice against someone constitutes murder to God. When we contain hatred in our hearts for another person, we commit the sin of murder in God's eyes (1 John 3:13-16). The referenced section pertains to Christians who have already said they trust in Jesus and therefore their lives should give evidence of righteousness at work. It doesn't even have to be visible outwardly. God sees it.