Rabah bin Abd al-Rahman bin Huwaytib narrates that his grandmother said: I heard the Prophet (peace and blessings be upon him) say: "The one who does not believe in me does not believe in Allah Almighty; the one who does not love the Ansar does not believe in me; there is no prayer for the one who has no ablution; and there is no ablution for the one who does not mention the name of Allah before it."
Ahmad recorded it from this same woman, in which she says: I heard the Prophet (peace and blessings be upon him) say it; and he also
recorded it from this woman, from her father. And Allah knows best. Its chain contains a narrator, Abu Thifal, about whom al-Bukhari (may Allah have mercy on him) said: There is a question about his narrations (fi hadithihi nazar). The rest of its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الطهارة / 1158