When a general expression is revealed in connection with a particular occasion, that occasion must necessarily be included within the scope of the expression.

Third:
Had slaughtering at the site of their festival been permissible, the Messenger of Allah—may Allah bless him and grant him peace—would have allowed the person who made the vow to fulfil it, just as he permitted the woman who vowed to beat the tambourine to carry out her vow. Indeed, he would have obliged its fulfilment, for slaughtering at the place stipulated in a vow is itself obligatory. Yet because slaughtering at the location of their festival is forbidden, how could it be admissible to concur with them on the very day of their festival by performing some of the deeds that are undertaken on account of it?

This is clarified by the fact that the term “festival” (ʿīd) refers to anything that recurs as a customary public gathering, whether that recurrence is annual, weekly, monthly, or the like. A festival therefore comprises several elements:
• a recurring day, such as the Day of Fitr or the day of Friday;
• a gathering held on that day; and
• actions that accompany it, whether acts of worship or social practices. A festival may also be tied to a particular place, or it may be unrestricted. All of these components may be designated a “festival.”

With regard to time, the Prophet—peace and blessings upon him—said of Friday: “This is a day that Allah has made a festival for the Muslims.” As for the gathering and the acts, Ibn ʿAbbas said: “I attended the festival with the Messenger of Allah—may Allah bless him and grant him peace.”