> ... they gave up their right to live ...

You’re stating a moral axiom, one that is widely and increasingly rejected in civilised countries.

Assuming you mean “capital punishment for intentional murderers” then how do you defend this? A murderer kills to satisfy some need, you appear to wish to death on someone to satisfy some need of your own ie “justice”, even presumably when you aren’t personally victimised by their crime.

It seems capital punishment creates at least two evils - an unnecessary taking of human life, and the encouragement of sadistic ideation in the general population.

Don't give me this "civilized countries" false dichotomy. It's not only condescending, but wrong.

Taking a life can be a necessary evil. In "civilized countries" as how you put it, the next of kin has the choice on whether to forgive the killer or take blood money, or have him executed by the court. This is for one on one incidents. For other cases, such as serial rapists or serial killers, the decision is 100% in the hands of the court, as it is way bigger than a single interaction.

Taking a life can be necessary to protect one’s life or the life of others, but that isn’t the case in capital punishment as someone in custody is no longer a mortal threat to society.

Regarding civilised or not, perhaps this might be of interest:

https://goodessaysblog.wordpress.com/2016/10/23/capital-puni...

As typical of many of these writers, he's clearly showing his bias when looking at the world (namely, from a secular Western sense). The fact that it is failing in the current secular societies does not mean that it is ineffective in other societies, or that it is in itself bad. We don't have the problems he listed in Islam for example.

> but that isn’t the case in capital punishment as someone in custody is no longer a mortal threat to society.

It's not just about being a threat, it's about justice.

And what do you do if a person is falsely accused?

Under Islamic rules, suspicion would fend off the Hadd punishment: https://sunnah.com/tirmidhi/17/2.

Then the life of the executioner must be taken as well. Unless of course, there is an exception granted, in which case the taking of a life isn’t necessarily grounds for execution, so there is no absolute truth to the matter and it is open for interpretation. It is not as simple as you make it sound.

No it's quite silly to talk in absolutes like that. The rule is that it is permitted to take life for justice. No one said that taking any life for any reason means that another life must be forfeit. The Quran is very clear on this: https://quran.com/17/33

Well my book says differently so yours is wrong.