An-Nisa 4:92 وما كان لمومن ان يقتل مومنا الا خطا ومن قتل مومنا خطا فتحرير رقبة مومنة ودية مسلمة الى اهله الا ان يصدقوا فان كان من قوم عدو لكم وهو مومن فتحرير رقبة مومنة وان كان من قوم بينكم وبينهم ميثاق فدية مسلمة الى اهله وتحرير رقبة مومنة فمن لم يجد فصيام شهرين متتابعين توبة من الله وكان الله عليما حكيما ٩٢

It is not for a believer to kill a believer unless (it be) by mistake. He who hath killed a believer by mistake must set free a believing slave, and pay the blood-money to the family of the slain, unless they remit it as a charity. If he (the victim) be of a people hostile unto you, and he is a believer, then (the penance is) to set free a believing slave. And if he cometh of a folk between whom and you there is a covenant, then the blood-money must be paid unto his folk and (also) a believing slave must be set free. And whoso hath not the wherewithal must fast two consecutive months. A penance from Allah. Allah is Knower, Wise.