Exodus 20:13: “You shall not murder. (ESV)
The sixth Commandment is simple enough. It is a prohibition against murder. The word is broad enough that it can be translated as "kill", although this specific term is the less common of the two Hebrew terms for “kill," “murder," or “slay."
Given the context of the other places in which this term is used, the prohibition here is not of all killing whatsoever. This term is used forty times in the Old Testament. Many of those references are dedicated to describing a person who has killed another and flees to what are called "cities of refuge" to avoid punishment. Numbers 35, Deuteronomy 19, and Joshua 20 all give instructions for the manslayer and cities of refuge. Interestingly, those chapters detail processes by which it can be determined whether the "manslayer" ought to be given up to the victim's avenger to be killed or allowed to remain in the city of refuge safe from revenge.
Killing Versus Murder
Not all killing is unjust. Genesis 9 outlines the terms of what is commonly called "capital punishment" today, and capital punishment in the sense that God describes is not unjust or wrong. There are also clear examples where killing is the right thing to do, such as cases in which God is the one who kills (e.g., Onan, the firstborn of Egypt, Nadab and Abihu, etc.). Human examples of times it was proper to kill would surely include David's killing of Goliath (1 Samuel 17) and Elijah's slaughter of the prophets of Baal (1 Kings 18).
Numbers 35:9-21 serves as an example of what the sixth commandment means when it is fleshed out. Not all killing is prohibited. Unintentional killing is undesirable, but not punishable by death. Premeditated murder, gross neglect, and aggravated murder are all punishable by death. But accidental killing, what we might call manslaughter, is not to be punished by death. And in cases where the motive and cause are unclear, the people were to use the Law's parameters to decide whether to rescue the manslayer or to hand him over to the avenger (Num. 35:9-29).
In addition, there is a specific allowance made in the Law for an avenger who kills the manslayer or murderer (Num. 35:27). If the killing perpetrated by the manslayer was murder and not an accident, then the avenger may kill the manslayer.
This short survey shows the prohibition against killing in the Decalogue was not a blanket command against all killing whatsoever. It is properly understood as a prohibition against murder.
The Sixth Commandment Today
It is easy to think this applies to many of us very little since we might think of murderers as those who belong in prison while the rest of us keep our hands off each other. But that is not true. Jesus applied the commandment much more broadly than that. And he did so in a way that makes most, perhaps even all, of us guilty of breaking this commandment.
In the Sermon on the Mount, Jesus speaks the well-known line, "You have heard that it was said..." Whenever we read those words, we know a significant turn is coming. Jesus goes on not to further restrict the meaning of the command against killing but to broaden it exponentially. Jesus says that anyone who is angry at, insults, or shouts, "You fool!" at his brother is in danger of hellfire (Matthew 5:22).
Notice that not only does Jesus expand our understanding of the command not to kill, but he also deepens the punishment. The Law threatened lawbreakers with capital punishment. Jesus threatens them with Hell.
What do we take from this? The principle that leads to murder works in all of us, even if it doesn't reach the point where we lift our hand against someone. When we have those pangs of hate and anger out of offense, frustration, or bitterness, we commit what we might call "mini-murders" against that person.
Jesus' words are very clear. When we find ourselves in these kinds of conflict with each other, we must seek to be reconciled. Amazingly, Jesus places a higher priority on reconciling with our brother than on worship (Matt. 5:23-24). The point seems to be that you cannot be at peace with God while you are not at peace with your brother. John capitalizes on this point in his first letter (1 John 3:14-15; 4:20).
John even makes the explicit point that anyone who hates his brother is a murderer, making it impossible for eternal life to abide in him (1 John 3:14-15). The force of Jesus' and John's words is frankly astounding. How can the language be so strong? Is it really impossible to love God and hate your brother? Yes, according to 1 John 4:20.
What do we make of this? All of us likely need to significantly increase the seriousness with which we treat conflict with each other. If we cannot make peace with each other but instead hold on to bitterness, wrath, anger, clamor, malice, and slander (cf. Eph. 4:31), it is no small matter. It is a question of whether or not we are Christians.
In living for God through Christ, we need to take this commandment seriously. As simple and far away as the idea of murdering someone feels from most of us, it is apparent that the principle in the heart that leads to murder in society resides within all of us. We are all capable of murder. Not only that, but there are likely those reading this article who began by assuming this was a faraway concept but did not understand they may be in danger of hellfire.
It is good to know how pervasive our sin is. So often, we fail to recognize the severity and acuteness of our sin. Thank God that Jesus clarified for us in his teaching. And even more, thank God that anyone who believes in Christ Jesus has an advocate in him when they sin (1 John 2:1-6).