and he says the prescribed supplication, …
His statement, “and he says the prescribed supplication,” refers to the hadith of Umar, may Allah be pleased with him: “I bear witness that there is no god worthy of worship but Allah, and I bear witness that Muhammad is His servant and Messenger. O Allah, make me among those who constantly repent, and make me among those who purify themselves. For whoever performs ablution thoroughly and then recites this remembrance, the eight gates of Paradise will be opened for him, and he may enter through whichever of them he wishes.” (1)
It is fitting that he recite this remembrance after ablution, because ablution purifies the body, whereas this remembrance purifies the heart, since it entails sincerity to Allah.
It also combines the supplication that Allah make him among those who constantly repent, who have purified their hearts, and among those who purify themselves, who have purified their bodies.
Some scholars said that this remembrance is also prescribed after the ritual bath and dry ablution (2), because the ritual bath includes ablution and more; for if
(1) Reported by Muslim, Book of Purification: Chapter on the Recommended Remembrance after Ablution, no. 234, without the words: “O Allah, make me among those who repent, and make me among those who purify themselves.” This addition was reported by al-Tirmidhi, Chapters on Purification: Chapter on What Is Said after Ablution, no. 55.
Al-Tirmidhi said: “There is inconsistency in its chain of transmission.”
Ibn Hajar said: “This addition is not established in this hadith, for Ja'far ibn Muhammad, al-Tirmidhi's shaykh, was alone in narrating it and did not preserve the chain accurately: he omitted Jubayr ibn Nufayr and Uqbah between Abu Idris and Umar. Thus, it became disconnected—indeed, mu'dal (a chain with two or more consecutive omitted narrators). Everyone who narrated it from Mu'awiyah ibn Salih, and then from Zayd ibn al-Hubab, contradicted him … The agreement of all of them is more weighty than the solitary narration of one person.” Nata'ij al-Afkar, 1:244.
It has a corroborating narration from the hadith of Thawban, reported by Ibn al-Sunni, no. 32. Its chain contains Abu Sa'd al-Baqqal, who is weak.
It also has another route recorded by al-Tabarani in al-Awsat, no. 4895, through al-A'mash, from Salim ibn Abi al-Ja'd, from Thawban. Ibn Hajar said: “Salim did not hear from Thawban, and the narrator who transmitted it from al-A'mash is not well known.”
(2) See al-Insaf, 1:365; al-Adhkar by al-Nawawi, p. 59.