The people of Kufa say: Do not prompt the imam. There is no harm in it; does he not say 'Subhan Allah'? Abu Dawud said: Abu Ishaq heard only four hadiths from al-Harith, and this is not one of them.

Section: If the imam is blocked [i.e., struggles to continue] during the Fatiha, those behind him are obligated to prompt him, just as if he forgot a prostration (sajdah), they are obligated to alert him with the tasbih. If he is unable to complete the Fatiha, he may appoint a successor (istikhlaf) to lead them in prayer; for it is a valid excuse, so it is permissible to appoint a successor because of it, just as if he were overcome by a hadath (state of ritual impurity). Likewise, if he becomes incapable during the prayer of performing an essential element (rukn) upon which following him depends, such as bowing (ruku') or prostration (sujud), he shall appoint a successor to complete the prayer for them, just as one who is overcome by a hadath; in fact, this is more appropriate for succession. [Because one who is overcome by a hadath has had his prayer invalidated, whereas this one's prayer is sound], [making him more worthy of succession. If he is unable to complete the Fatiha, Ibn 'Aqil said: He should recite what he is able to recite], and that which he is unable to recite is waived, and his prayer is valid; for the recitation is an essential element (rukn) that he became incapable of during the prayer, so it is waived just like the standing (qiyam). As for the follower (ma'mum), if he is an ummi (illiterate/unable) incapable of reciting the Fatiha, his prayer is also valid. But if he is capable of recitation, he intends to sever his following (mufaraqah) and completes it alone; it is not valid for him to complete the prayer behind him, because the ruling on him has become like that of the ummi. The correct view is that if he is unable to recite the Fatiha, his prayer is invalidated because he is capable of the prayer with its recitation, so his prayer is not valid without it, due to the generality of his saying (peace and blessings of Allah be upon him): 'There is no prayer for one who does not recite the Opening of the Book (Fatiha al-Kitab).' It is not valid to draw an analogy between this and the ummi; for if the ummi were capable of learning it before the time expires, his prayer would not be valid without it, and this [person] is able to depart [the prayer], ask about what he stopped at, and pray. Nor is it valid to draw an analogy between this and the essential elements of physical actions (arkan al-af'al); for his exiting the prayer does not remove his incapacity to perform it, and he is not secure from the recurrence of such incapacity, unlike this case. The second type is that which...