What is self-defense? What does Islam say about killing a person in self-defense?

The act of killing a person and ending his/her life is the task of the judiciary. 

No one can kill a person or end one’s life claiming that s/he deserves death, judging by his/her own criteria and opinion. If s/he does, s/he becomes a murderer and deserves the punishment for that murder. S/he is treated as a murderer both in the world and in the Hereafter. S/he undertakes the sins of the person s/he killed and compensates for it by going through severe punishment. 

However, there are some obligatory situations, in which resisting becomes lawful due to obligation and killer can be freed from punishment. 

Let us list some of those exceptional situations: 

1-      If one takes action to kill another and the other person cannot escape though he has tried every possible way and eventually has to kill the aggressor; neither retribution nor blood money is necessary. 

This is because the murdered person took the first action to kill the other and there was no other option which could dissuade him from killing; and here the obligation of self-defense emerged. However, if it was possible to send the aggressor away by shouting and calling people around for help and the person killed the aggressor without trying this option, it is not self-defense but murder. 

2-      If an armed conflict occurred while someone was fighting a man who entered his shop, house or a store where he kept his possessions with the purpose of burglary and the owner killed the burglar who wanted to steal his possessions, it is called the right to defend one’s property. The owner of the property who killed the burglar is not considered a murderer; he is regarded to have made a lawful defense of property. It requires neither retribution nor blood money. The burglar shed his blood for nothing. 

3-      If a person resists someone who tends to rape his/her honor in his/her house or somewhere else and kills the aggressor while trying to protect his/her honor, it does not require retribution or blood money as defending one’s honor is a lawful defense. This is because s/he had no other choice than killing the aggressor in order to defend his/her honor. 

In conclusion, it an indisputable right of everyone to defend their life, property and honor. If one kills the aggressor while defending those, s/he is not murderer and if s/he is killed by the aggressor, s/he is considered a martyr. 

(See. Abdulkâdir Üdeh, et-Teşrîu'l-Cinâî'l-İslâmî, Kâhire 1959, 1/473, 489; Abdulkerîm Zeydan, Hâletu'd-Darûra fi'ş-Şerîatil İslâmiyye (Mecmûatu Buhüsil-Fıkhiyye, along with his 8 articles), Beyrut 1986, s. 184-195)