It is not for a believer to kill a believer except [that it be] by mistake; and whosoever kills a believer by mistake [it is ordained that] he must set free a believing slave and a compensation [blood-money] be given to the deceased’s family unless they remit it. If the deceased belonged to a people at war with you and he was a believer the freeing of a believing slave [is prescribed]; and if he belonged to a people with whom you have treaty of mutual alliance compensation [blood-money] must be paid to his family and believing slave must be freed. And whoso find this beyond his means he must fast for two consecutive months in order to seek repentance from Allah [swt]. And Allah [swt] is Ever All-Knowing, All-Wise.
And don’t be weak in the pursuit of the enemy; if you are suffering, then surely they are suffering as you are suffering, but you have hope from Allah [swt] that for which they hope not; and Allah [swt] is Ever All-Knowing, All-Wise.
And whoever earns sin he earns it only against himself. And Allah [swt] is Ever All-Knowing, All-Wise.