An-Nisaa 4:92

It is not for a believer to kill another believer except by mistake. Whoever kills a believer by mistake[67] must free a believing slave and pay blood money to his family, unless they waive it as an act of charity. But if the victim was a believer and belonged to people at war with you, then a believing slave must be freed. If he belonged to a people with whom you have a treaty, then blood money must be paid to his family and the freeing of a believing slave. Anyone who is unable must fast for two consecutive months[68] by way of repentance to Allah. And Allah is All-Knowing, All-Wise.

[67] Inadvertent manslaughter usually results from some degree of negligence or error, thus, this punishment is ordained for not being cautious enough.
[68] Uninterrupted fast except when there is a valid reason, e.g., illness, menses for women etc.

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,[209] [seeking] acceptance of repentance from Allāh.[210] And Allāh is ever Knowing and Wise.

[209] Uninterrupted except when there is an Islāmically valid reason, as in Ramaḍān.
[210] An accidental death usually results from some degree of negligence or error for which the believer feels the need to repent.

92. 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.

It is not for a believer to kill a believer unless (it be) by mistake. He who hath killed a believer by mistake must set free a believing slave, and pay the blood-money to the family of the slain, unless they remit it as a charity. If he (the victim) be of a people hostile unto you, and he is a believer, then (the penance is) to set free a believing slave. And if he cometh of a folk between whom and you there is a covenant, then the blood-money must be paid unto his folk and (also) a believing slave must be set free. And whoso hath not the wherewithal must fast two consecutive months. A penance from Allah. Allah is Knower, Wise.