his prayer is not invalidated. This is the view of Ibn Umar, Ata', Sa'id ibn al-Musayyib, Salim, Mujahid, al-Sha'bi, al-Nakha'i, al-Zuhri, Yahya al-Ansari, Ishaq, and Ibn al-Mundhir. The second [view]: he must repeat it. This is the view of Abu Qilaba and al-Shafi'i; because it is a purification required for prayer, so it does not lapse due to ignorance of it, like purity from ritual impurity (hadath). Rabi'ah and Malik said: He repeats what was during the time [of the prayer], and does not repeat it after it has passed. The basis for the first narration is what Abu Sa'id reported, who said: While the Messenger of Allah (may Allah bless him and grant him peace) was leading his companions in prayer, he took off his sandals and placed them to his left, [and the people took off their sandals] (7). When the Messenger of Allah (may Allah bless him and grant him peace) finished his prayer, he said: "What caused you to take off your sandals?" They said: "We saw you take off your sandals, so we took off ours." He said: "Gabriel came to me and informed me that there was filth on them." Recorded by Abu Dawud (8). If purity were a condition regardless of knowledge of it, he would have been required to restart the prayer. This differs from purity from ritual impurity; because it is more emphasized, as no pardon is granted for even a small amount of it, and it is specific to the body. If he knew of the impurity then forgot it (9), the Qadi said: Our companions have recounted two narrations regarding these two matters. He mentioned in the matter of forgetfulness that the prayer is void, because he is attributed with negligence, unlike the one who is ignorant of it. Al-Amidi said: He must repeat it if he was slothful, which is a single narration. The correct view is that both are treated the same, because whatever one is excused for due to ignorance, one is also excused for due to forgetfulness. In fact, forgetfulness is more deserving of excuse, because of the arrival of the text granting pardon for it, in the statement of the Prophet (may Allah bless him and grant him peace): "My nation has been pardoned for errors and forgetfulness" (10). If he learns of the impurity during the prayer, then if we say he is excused, his prayer is valid. Then, if it is possible for him to remove the impurity without a long delay or excessive movement, he should remove it and resume [the prayer], just as the Prophet (may Allah bless him and grant him peace) took off his sandals when Gabriel informed him of the filth on them. If he needs to do either of these [i.e., long delay or excessive movement], his prayer is invalidated; because it leads to one of two things: either