The view of the madhhab appears—and Allah knows best—to be closer to what is correct, because water has been found, and the Prophet ﷺ said: “If he finds water, let him fear Allah and let it touch his skin.” (1) Moreover, his leaving the prayer at that point is in order to complete it, not to invalidate it—just as some scholars have said regarding one who begins praying alone and then a congregation arrives: he may discontinue it in order to pray with the congregation. (2)
Not after it
His statement, “not after it,” means that if he finds water after the prayer, he is not required to repeat it. What is not meant, despite what his wording may seem to suggest, is that dry ablution is not invalidated.
The evidence for this is the report narrated by Abu Dawud concerning the two men who performed dry ablution and then prayed, after which they found water while there was still time remaining. One of them did not repeat the prayer, while the other performed ablution and repeated it. They then came to the Prophet ﷺ and informed him of what had happened. He said to the one who had not repeated it, “You have followed the sunnah correctly,” and he said to the one who had repeated it, “You will have the reward twice over.” (3)
(1) Its sourcing was mentioned previously; see p. 374.
(2) See al-Insaf, 3:372; al-Iqna, 1:163.
(3) Reported by Abu Dawud, Book of Purification, chapter: “The person performing tayammum who finds water after praying within the prayer time,” no. 338; al-Nasai, Book of Ghusl, chapter: “Tayammum for one who finds water after the prayer,” 1:212, no. 431; al-Darimi, no. 744; and al-Hakim, 1:9, 178, through Abd Allah ibn Nafi, from al-Layth, from Bakr ibn Sawadah, from Ata, from Abu Said al-Khudri, in a marfu report attributed to the Prophet.
It has been criticized on the grounds that Abd Allah ibn Nafi was alone in narrating it with a connected chain. Abd Allah ibn al-Mubarak and Yahya ibn Bukayr differed from him, narrating it from al-Layth, from Umayrah ibn Abi Najiyah, from Bakr ibn Sawadah, from Ata ibn Yasar, from the Prophet as a mursal report with a broken chain.
Abu Dawud said: “The mention of Abu Said in this hadith is an error and is not preserved; it is mursal.” It was also narrated with a connected chain through al-Layth and Ibn Lahiah, but the suitability of all these routes for corroboration is open to question. See Fath al-Bari by Ibn Rajab, 2:37; Bayan al-Wahm wa al-Iham, no. 440; Nasb al-Rayah, 1:160; al-Talkhis al-Habir, no. 213.