As for the conditions of obligation and validity that are peculiar to the Friday Prayer, everyone agrees that a congregation is required, yet they dispute over the number that constitutes such a congregation.
Some maintain that it is fulfilled by one person in addition to the imam; this is the view of al-Ṭabarī. Others say it requires two besides the imam. A third position holds that three other than the imam are necessary, the opinion of Abū Ḥanīfah. Still others stipulate forty, a view ascribed to al-Shāfiʿī and Aḥmad, while another group sets the minimum at thirty. A further opinion, adopted by Mālik, fixes no specific figure yet rules that fewer than forty will suffice, though not as few as three or four; he defines the number as those by whom a village could properly subsist.
Their disagreement turns on what constitutes the least number to which the word “gathering” (jamʿ) may be applied: is it three, four, or merely two? And does the imam count as part of that number or not? Likewise, does the Shariah require only the bare minimum to which the term ordinarily applies, or the larger number that common usage associates with it—something beyond three or four?
Hence, whoever argues that the condition is simply the smallest number called a gathering and holds that this minimum is two will say, if he includes the imam, that Jumuʿah is established with the imam and one other. If he does not include the imam, he will require two in addition to the imam. The same reasoning applies to those who deem the minimum to be three: if they exclude the imam, they demand three besides him; but if they include him, their view coincides with the earlier opinion that set the minimum at two while excluding the imam.
By contrast, the scholar who looked to the number ordinarily designated a “gathering” in most circumstances asserted that the prayer is not valid with two or even four, yet he set no exact limit. Because he also considered permanent settlement a prerequisite, he defined the required congregation as the number of people by whom an independent community could be maintained—and that is Mālik, may Allah have mercy on him.
Those who stipulated forty relied on the report that this was the number present at the very first Friday Prayer performed for the people.
This, then, is one of the conditions of the Friday Prayer—meaning a condition both of obligation and of validity—for some conditions pertain only to obligation, whereas others combine both aspects.
The second condition is residence. The jurists of the major cities concur on this, agreeing that Jumuʿah is not obligatory for a traveller. The Ẓāhirīs diverged, obligating the Friday Prayer even upon the traveller. Abū Ḥanīfah, moreover, required that it be held in a recognised city and in the presence of the governing authority, though he did not stipulate any particular number of worshippers.