He—may Allah Most High have mercy on him—was asked:

Must someone who kills deliberately or accidentally perform the expiation mentioned in the Quran—“fasting for two consecutive months”—or is he required to pay blood money?

He replied:

“Accidental killing” entails only blood money and expiation; no sin attaches to it. Someone who kills deliberately, however, incurs sin. If the victim’s heirs pardon him or accept blood money, this does not extinguish the victim’s claim in the Hereafter. If they put him to death, there is disagreement within Ahmad’s school as to whether that claim is extinguished. The stronger view is that it is not. However, if the killer has many good deeds, enough of them will be taken from him to satisfy the victim; or Allah will compensate the victim from His own bounty if the killer sincerely repents.

Blood money is obligatory for someone who kills accidentally, according to the explicit text of the Quran and the consensus of the Muslim community. Blood money is due for both a Muslim and a person protected by a treaty, as the Quran indicates. This is the position of the early generations and the imams, and no disagreement among the earlier scholars is known on this matter. Some later Zāhirīs, however, claimed that no blood money is due for the latter.