وَمَاكَانَلِمُؤْمِنٍأَنيَقْتُلَمُؤْمِنًاإِلَّاخَطَـًۭٔا ۚوَمَنقَتَلَمُؤْمِنًاخَطَـًۭٔافَتَحْرِيرُرَقَبَةٍۢمُّؤْمِنَةٍۢوَدِيَةٌۭمُّسَلَّمَةٌإِلَىٰٓأَهْلِهِۦٓإِلَّآأَنيَصَّدَّقُوا۟ ۚفَإِنكَانَمِنقَوْمٍعَدُوٍّۢلَّكُمْوَهُوَمُؤْمِنٌۭفَتَحْرِيرُرَقَبَةٍۢمُّؤْمِنَةٍۢ ۖوَإِنكَانَمِنقَوْمٍۭبَيْنَكُمْوَبَيْنَهُممِّيثَـٰقٌۭفَدِيَةٌۭمُّسَلَّمَةٌإِلَىٰٓأَهْلِهِۦوَتَحْرِيرُرَقَبَةٍۢمُّؤْمِنَةٍۢ ۖفَمَنلَّمْيَجِدْفَصِيَامُشَهْرَيْنِمُتَتَابِعَيْنِتَوْبَةًۭمِّنَٱللَّهِ ۗوَكَانَٱللَّهُعَلِيمًاحَكِيمًۭا٩٢

And never is it for a believer to kill a believer except by mistake. And whoever kills a believer by mistake - then the freeing of a believing slave and a compensation payment [diyah] presented to his [i.e., the deceased's] family [is required], unless they give [up their right as] charity. But if he [i.e., the deceased] was from a people at war with you and he was a believer - then [only] the freeing of a believing slave; and if he was from a people with whom you have a treaty - then a compensation payment presented to his family and the freeing of a believing slave. And whoever does not find [one or cannot afford to buy one] - then [instead], a fast for two months consecutively,¹ [seeking] acceptance of repentance from Allāh.² And Allāh is ever Knowing and Wise.

But whoever kills a believer intentionally - his recompense is Hell, wherein he will abide eternally, and Allāh has become angry with him and has cursed him and has prepared for him a great punishment.

O you who have believed, when you go forth [to fight] in the cause of Allāh, investigate; and do not say to one who gives you [a greeting of] peace, "You are not a believer,"¹ aspiring for the goods of worldly life; for with Allāh are many acquisitions. You [yourselves] were like that before; then Allāh conferred His favor [i.e., guidance] upon you, so investigate. Indeed Allāh is ever, of what you do, Aware.