The 5th Commandment: Thou Shalt Not Kill

​Thou shalt not kill. – Exodus 20:13
 
            The Sacred Scriptures depict life, especially human life, as being holy, sacred, set apart for God. God created everything that exists as good, but when He created humanity He did something different; He created mankind “in our image, after our likeness” (Gn 1:26), and breathed life into us Himself (Gn 2:7). The Bible goes on to depict all of humanity, whatever nation we come from, as one family. All of humanity comes from our common first parents, Adam and Eve, and all murder is seen through the story of Cain and Abel (Gn 4), which was fratricide, brother killing brother. Later, murder and warfare in the world leads to the great flood (Gn 6:11), so that God begins again with Noah and his family, once again depicting all of humanity and the many nations of the world coming from one common family (Gn 10). In the Biblical perspective murder is wrong because every life comes from God, is created in His image and likeness, and therefore possesses human dignity. We’re called to treat one another as brothers and sisters, not competing for resources, honor, or power, but cooperating with one another and treating others as we would have them treat ourselves.
            Murder is defined as directly destroying an innocent human being (CCC 2258). Murder is inherently evil and can’t be justified under any circumstances. When someone tries to justify murder they’ll usually argue that it doesn’t fit some part of that definition. They may say that it’s not directly destroying the life because they were “only following orders” or “they made me do it.” They may say that no one is truly innocent. Finally, they may argue, as the Nazi’s did, that their victims aren’t truly human or that they’re less than us in some way.
            God wants us to have peace with one another, but He also understands that life isn’t that simple. The Bible clearly shows instances of legitimate self-defense, for example in David and Goliath (1 Sam 17:41-54) or Sampson and the Philistines (Jdg 16:23-31). However, we must keep in mind what the Catechism says: 
 
If a man in self-defense uses more than necessary violence, it will be unlawful: whereas if he repels force with moderation, his defense will be lawful...Nor is it necessary for salvation that a man omit the act of moderate self-defense to avoid killing the other man, since one is bound to take more care of one’s own life than of another’s. Legitimate defense can be not only a right but a grave duty for someone responsible for another’s life. Preserving the common good requires rendering the unjust aggressor unable to inflict harm. To this end, those holding legitimate authority have the right to repel by armed force aggressors against the civil community entrusted to their charge. – CCC 2264-65
 
            Therefore, we have a right to protect ourselves form harm by driving someone off or retendering them unable to harm us, but killing someone when we don’t have to is not legitimate self-defense. This is not a defense of killing someone in an honor duel or over an insult, but in defense of our person or those whom we’re responsible for. Notice that I’m talking about Christian morality, not civil law. The law in your area may be more or less restrictive on the right to self-defense. 
            The purpose of this reflection is simply to give the basics of Church teaching on the 5th Commandment, and to give us some things to reflect on. We do have a responsibility to our brothers and sisters in the world, to treat one another with respect and dignity, and to love our neighbor as ourselves. For a more complete look at the 5th Commandment, see the Catechism of the Catholic Church numbers 2258 through 2330.