It is not for a believer (Muslim) to kill any believer, except by mistake. Whoever kills a believer by mistake, then, a believing slave has to be freed, and the blood money must be paid to his family, unless they forgo it. If he (the victim) belongs to a people hostile to you and is a believer, then, a believing slave has to be freed. If he (the victim) belongs to a people between whom and you there is treaty, then, blood money is to be paid to his family, and a believing slave to be freed. Whoever does not find one has to fast for two consecutive months. This is repentance prescribed from Allah‘s side. Allah is All-Knowing, All-Wise.