It is not lawful for a believer to kill a believer, unless it happen by mistake; and whoso killeth a believer by mistake, the penalty shall be the freeing of a believer from slavery, and a fine to be paid to the family of the deceased, unless they remit it as alms: And if the slain person be of a people at enmity with you, and be a true believer, the penalty shall be the freeing of a believer; but if he be of a people in confederacy with you, a fine to be paid to his family, and the freeing of a believer. And he who findeth not wherewith to do this, shall fast two months consecutively, as a penance enjoined from God; and God is knowing and wise.