There is no dispute among the scholars that the “numbered days” are the Tashrīq days and that they are three days following the Day of Sacrifice. The sole exception is the report from Saʿīd ibn Jubayr, who said, “The Day of Sacrifice itself is one of the Tashrīq days.” Their disagreement concerns only the identity of the “known days,” in accordance with the two opinions cited earlier.

Those who limit the sacrifice to the Day of Sacrifice alone do so on the basis that the “known days” are the first ten days of Dhul-Ḥijjah. They argue: “Consensus has been reached that, within those ten, slaughter is permissible only on the tenth day, which is the expressly designated time for offering; therefore slaughter must be confined to the Day of Sacrifice.”

The third issue is their difference over the nights that fall between the sacrificial days. In Mālik’s well-known view it is not permissible to slaughter during the nights of either the Day of Sacrifice or the Tashrīq days, whereas al-Shāfiʿī and a number of scholars deemed it permissible.

The cause of their disagreement lies in the dual usage of the Arabic word yawm (“day”). At times the Arabs apply it to both the daylight hours and the ensuing night, as in the verse, “Enjoy yourselves in your homes for three days” (Hūd 65). At other times they restrict it to the daylight hours alone, excluding the night, as in His saying, “He unleashed it upon them for seven nights and eight days, unrelenting” (al-Ḥāqqah 7).

Accordingly, whoever understands yawm in the verse “and mention the name of Allah during known days” (al-Ḥajj 28) to include both day and night holds that slaughter is permissible by night as well as by day. Conversely, whoever holds that in this verse yawm excludes the night rules that slaughter is not allowed at night.

The question, then, is whether the term yawm is more emphatically indicative of one meaning than the other. It appears stronger in reference to daytime than to night. Yet even if we concede that in the verse it denotes daytime only, the prohibition of night-time slaughter would rest on a very weak form of argument—namely, inferring the opposite ruling from the negation implied by the wording. This type of inference is among the weakest, to the point that the scholars say none of the theologians relied on it except al-Daqqāq.

Someone might counter that the default with respect to slaughter is prohibition, and that permission has been established for the daytime; hence the burden of proof falls on anyone who permits it at night.

As for the one who actually performs the slaughter, the scholars recommend that the person offering the sacrifice do the slaughter himself if able, though they agree that he may appoint someone else. They disagreed, however, about a case in which another person slaughters without the owner’s permission. One opinion holds that such a sacrifice is invalid. Another view distinguishes between a close friend or a child, and a stranger—allowing it in the first two cases. So far as I am aware, all schools agree that if a stranger slaughters without permission, the sacrifice is invalid.