I add: It is actually reported that Abu Yusuf once performed the congregational prayer behind the caliph Harun al-Rashid after the latter had undergone cupping. Malik had issued a ruling for the caliph that no new wudu (ritual ablution) was required; Abu Yusuf therefore prayed behind him and did not repeat the prayer. Ahmad ibn Hanbal, for his part, held that cupping or a nose-bleed does require wudu. When someone asked him, “Suppose the imam’s blood flows and he does not perform wudu, then you pray behind him?” he replied, “Why should I not pray behind Sa id ibn al-Musayyab and Malik?!” In sum, the position adopted by Abu Bakr al-Razi the Hanafi and Abu Bakr al-Qaffal—despite differing from what is commonly ascribed to their schools—is the correct view, and it is also the view of Malik and Ahmad. Two reasons support this: 1. To hold the contrary opinion is a religious innovation (bid a) never affirmed by any of the righteous predecessors, as already noted. Ibn Mas ud said, “Follow and do not innovate; you have been given all you need. Hold fast to the ancient way.” That “ancient way” is precisely this doctrine. 2. The Prophet said, “They lead you in prayer; if they are correct you and they receive the reward, and if they err you receive the reward and the burden falls upon them.” Reported by al-Bukhari (2/149) and Ahmad (2/355, this wording). Ibn al-Mundhir commented, “This hadith refutes those who claim that if the imam’s prayer is invalid, the prayers of those behind him are likewise invalid” (Fath, 2/149). Shaykh al-Islam stated in his Fatawa (2/381), “The Prophet made it clear that the imam’s mistake does not extend to the follower. The follower believes that what the imam has done is permissible for him and that he incurs no sin thereby, for the imam is either a mujtahid or someone imitating a mujtahid. Knowing that Allah has pardoned the imam’s error, the follower is convinced of the prayer’s validity and feels no obligation to repeat it. Indeed, were the imam to issue a legal judgment on the same basis, it would not be permissible to overturn it; rather, it would have to be executed.”