And it does not behoove a believer to kill a believer except by mistake, and whoever kills a believer by mistake, he should free a believing slave, and blood-money should be paid to his people unless they remit it as alms; but if he be from a tribe hostile to you and he is a believer, the freeing of a believing slave (suffices), and if he is from a tribe between whom and you there is a convenant, the blood-money should be paid to his people along with the freeing of a believing slave; but he who cannot find (a slave) should fast for two months successively: a penance from Allah, and Allah is Knowing, Wise.

Surely the number of months with Allah is twelve months in Allah's ordinance since the day when He created the heavens and the earth, of these four being sacred; that is the right reckoning; therefore be not unjust to yourselves regarding them, and fight the polytheists all together as they fight you all together; and know that Allah is with those who guard (against evil).