Why is killing not always considered evil?


I’ve always wondered about this.

I get that it is permitted in certain circumstances, self-defense, protection of others, just war eTC… the intention may not be to kill but it’s a double effect

but traditional catholic thought has taught that lying for example, is always evil and that the ends do not justify the means. but wouldn’t the same arguments apply, you could lie in self-defense or protection of others, the intention may also not be to lie but you have to resort to it.

can anyone help explain this to me?


Lying is always intrinsically evil. That does not mean that it is always a mortal sin, just that it is always grave matter. (also don’t get lying mixed up with deception).

If I remember from my moral theology lesson, I think that lying is always intrinsically evil because God cannot lie, making it of evil (lack of good) origin? (Again correct me if I’m wrong in saying this…my specialty does not lie in the moral theology spot).

Now as for killing, you cannot mix that with murder. Murder is the ultimate intention of ending one’s life for the sake of ending it (either just because or for other reasons such as anger, jealousy, etc.). Killing however is not the intent of ending the person’s life for no good reason, but rather a double effect (like you said). To stop terror, someone that is committing this terror fully may need to be killed.

As to why killing is not intrinsically evil can be (maybe) because God can end life whenever he wants to. For instance read anywhere in the Old Testament (:D) and God is said to have “killed” “destroyed” or “ended” life. But we all know that saying God killed someone is limiting God to human conditions, which is obviously sort of a fallacy. But just as God can justly take away human life (for the sake of being the creator) he can allow humans to also partake in this just act against evil. It’s kind of like how God made the Ten Commandments and yet still gives the Catholic Church authority to create Laws and Doctrines that need to be followed.

Again, correct me if I’m wrong, but I think this should do a decent job of summarizing.



what’s the difference then? if not alld deception is lying?


The reason killing is not always wrong is that human life, in its earthly state, requires a civil society; that society requires laws; and laws, to be effective, require to be upheld, sometimes by killing.

If it is never acceptable to kill, then there can be no civil society (the question then being who has that authority and under what conditions).

While lying seeming to be “more evil” than killing also seems too difficult for me to accept, one explanation might be: human life in its natural-body form is inherently temporal, so upholding it is not always paramount; whereas truth is eternal, and so upholding truth should be.



Would it be evil if the murderer asked you if there were others hiding in your house and you said no?

You are deceiving him. It is your act evil?

If the murderer is going to kill your spouse and you kill him first to prevent that, are you committing evil?

I think it’s important to think about terminology and know exactly what it is you are asking:

grave matter,

these are all different things, related to one another, but different.


I have frequently read and have been told by priests who are scripture scholars, that the Commandment reads “Thou shalt not murder” rather than the familiar “Thou shall not kill.”

This would make more sense. We ARE permitted to take a life in defense of our own or another’s life, we ARE permitted to fight in a just war, and Jesus never did abrogate any of the Ten Commandments–they are still the moral law. Killing for just reasons is permitted–murder is not.

There can be a problem, though, if one is killing in defense, that it can become an act of revenge rather than justice. A soldier shoots and kills an enemy soldier. But a soldier does not have justification for hacking up the body of the person he killed out of hate or revenge, etc.


that’s why I’m trying to figure out.

current catholic thought seems ot say that killing is not always wrong but lying is. there is not much clarification on this issue. and st. Augustine and st. Thomas Aquinas taught is was never allowable to tell a lie, even ot save a person’s life

I don’t know, I’m just confused


The confusion is the nuance of the meanings of the words.
Without researching the Saints you reference, it would seem to me lying is probably used to mean a deception with evil intent.

Deceiving to save a life is not evil. So if you used the word “lying” in this instance, the “lie” would not be evil.

Killing is not always murder. Murder is always evil.


Try thinking of it this way…

I know this may not technically theologically correct, but it helps me understand it.

Killing is always a gave matter, but not always a mortal sin.

Murder is always a grave matter and is always a mortal sin.

Even justified killing can become murder depending on the motivations.

I pray this is helpful


The best place to find an in depth summary of this is the CCC.
“The Morality of Human Acts”


what about lying? always grave matter and mortal sin?


I would say that lying is always a grave matter but NOT always a mortal sin.


Let us use a little common sense here. Take that terribly worn out argument: If a person were hiding Jews in his basement and the Nazi came knocking at the door, is lying a sin.

God is not stupid and neither are we.


Exactly! I highly doubt that after that person died, God would say, “Well you saved 20 innocent Jews that one day, but you lied to do it… TO HELL WITH YOU!”

The God we know is a just and merciful one, let’s remember that


This is why it’s important to understand and specify how we are using words. Otherwise we go around in circles.


according to Aquinas and augustine, it would not be permissible to do that.


probably depends on the lie too, right?

telling you mom you didn’t eat an extra piece of candy when you did might not have the same moral weight as lying about taking money from your boss.

but I could be wrong.


Your scruples are acting up.
Your responses clearly show you do know the answer to this question.
Common sense.


though, realistically speaking, I very highly doubt if you just told Nazis there were no jews in your house, they would just go away without checking


They would indeed check, but the Jews might be well-enough hidden to escape notice. I imagine the search might be more thorough if you told the truth, or declined to answer.

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