Quran — Page 93
Uthmani · القرآن الكريم برسم العثماني (uthmani)
AND IT IS not conceivable that a believer should slay another believer, unless it be by mistake. And upon him who has slain a believer by mistake there is the duty of freeing a believing soul from bondage and paying an indemnity to the victim's relations, unless they forgo it by way of charity. Now if the slain, while himself a believer, belonged to a people who are at war with you, [the penance shall be confined to] the freeing of a believing soul from bondage; whereas, if he belonged to a people to whom you are bound by a covenant, [it shall consist of] an indemnity to be paid to his relations in addition to the freeing of a believing soul from bondage. And he who does not have the wherewithal shall fast [instead] for two consecutive months. (This is) the atonement ordained by God: and God is indeed all-knowing, wise.
But whoever deliberately slays another believer, his requital shall be hell, therein to abide; and God will condemn him, and will reject him, and will prepare for him awesome suffering.
[Hence,] O you who have attained to faith, when you go forth [to war] in God's cause, use your discernment, and do not - out of a desire for the fleeting gains of this worldly life - say unto anyone who offers you the greeting of peace, "Thou art not a believer" for with God there are gains abundant. You, too, were once in the same condition - but God has been gracious unto you. Use, therefore, your discernment: verily, God is always aware of what you do.
Muhammad Asad · Asad