وَمَا كَانَ لِمُؤْمِنٍ أَن يَقْتُلَ مُؤْمِنًا إِلَّا خَطَـًٔا ۚ وَمَن قَتَلَ مُؤْمِنًا خَطَـًٔا فَتَحْرِيرُ رَقَبَةٍ مُّؤْمِنَةٍ وَدِيَةٌ مُّسَلَّمَةٌ إِلَىٰٓ أَهْلِهِۦٓ إِلَّآ أَن يَصَّدَّقُوا۟ ۚ فَإِن كَانَ مِن قَوْمٍ عَدُوٍّ لَّكُمْ وَهُوَ مُؤْمِنٌ فَتَحْرِيرُ رَقَبَةٍ مُّؤْمِنَةٍ ۖ وَإِن كَانَ مِن قَوْمٍۭ بَيْنَكُمْ وَبَيْنَهُم مِّيثَـٰقٌ فَدِيَةٌ مُّسَلَّمَةٌ إِلَىٰٓ أَهْلِهِۦ وَتَحْرِيرُ رَقَبَةٍ مُّؤْمِنَةٍ ۖ فَمَن لَّمْ يَجِدْ فَصِيَامُ شَهْرَيْنِ مُتَتَابِعَيْنِ تَوْبَةً مِّنَ ٱللَّهِ ۗ وَكَانَ ٱللَّهُ عَلِيمًا حَكِيمًا
wamā kāna limu'minin an yaqtula mu'minan illā khaṭa-an waman qatala mu'minan khaṭa-an fataḥrīru raqabatin mu'minatin wadiyatun musallamatun ilā ahlihi illā an yaṣṣaddaqū fa-in kāna min qawmin ʿaduwwin lakum wahuwa mu'minun fataḥrīru raqabatin mu'minatin wa-in kāna min qawmin baynakum wabaynahum mīthāqun fadiyatun musallamatun ilā ahlihi wataḥrīru raqabatin mu'minatin faman lam yajid faṣiyāmu shahrayni mutatābiʿayni tawbatan mina l-lahi wakāna l-lahu ʿalīman ḥakīman
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, [seeking] acceptance of repentance from Allāh. And Allāh is ever Knowing and Wise.
— Saheeh International
Never should a believer kill another believer, except by mistake. If anyone kills a believer by mistake he must free one Muslim slave and pay compensation to the victim’s relatives, unless they charitably forgo it; if the victim belonged to a people at war with you but is a believer, then the compensation is only to free a believing slave; if he belonged to a people with whom you have a treaty, then compensation should be handed over to his relatives, and a believing slave set free. Anyone who lacks the means to do this must fast for two consecutive months by way of repentance to God: God is all knowing, all wise.
— M. A. S. Abdel Haleem
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, i.e. Diya) 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 a treaty of mutual alliance, compensation (blood-money - Diya) must be paid to his family, and a believing slave must be freed. And whoso finds this (the penance of freeing a slave) beyond his means, he must fast for two consecutive months in order to seek repentance from Allâh. And Allâh is Ever All-Knowing, All-Wise.
— Muhammad Muhsin Khan & Muhammad Taqi-ud-Din al-Hilali