Al-Baqarah 2:178

Ya ayyuha allatheena amanookutiba AAalaykumu alqisasu fee alqatla alhurrubilhurri walAAabdu bilAAabdi walonthabilontha faman AAufiya lahu min akheehi shay-on fattibaAAunbilmaAAroofi waadaon ilayhi bi-ihsaninthalika takhfeefun min rabbikum warahmatun famaniiAAtada baAAda thalika falahu AAathabunaleem

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.

O you who believe, QiSāS has been prescribed for you in the case of murdered people: The freeman (will be killed) for the freeman, the slave for the slave, and the female for the female. However, if one is somewhat forgiven by his brother, the recourse (of the latter) is to pursue the former (for blood money) with fairness, and the obligation (of the former) is to pay (it) to the latter in a nice way. That is a relief from your Lord, and a mercy. So, whoever transgresses after all that will have a painful punishment.