O you who have believed, prescribed for you is legal retribution for those murdered - the free for the free, the slave for the slave, and the female for the female. But whoever overlooks from his brother [i.e., the killer] anything, then there should be a suitable follow-up and payment to him [i.e., the deceased's heir or legal representative] with good conduct. This is an alleviation from your Lord and a mercy. But whoever transgresses after that will have a painful punishment.

Sahih International