ibn Nasī, from ʿAbd al-Raḥmān ibn Ghanm, from him, with the same wording.
Al-Aswad is Ibn Thalabah, a Syrian.
I say: al-Ḥākim (1/176) also narrated it through this route, but he recorded: “Baqiyyah ibn al-Walīd narrated to us; al-Aswad ibn Thalabah informed me of it.”
I do not know whether this is how the report actually stands in his copy, or whether the name of ʿAlī ibn ʿAlī has dropped out of our manuscript. Nor does he provide the second chain. He then said:
“Muslim has cited Baqiyyah ibn al-Walīd for corroboration, and as for al-Aswad ibn Thalabah, he is a well-known Syrian.”
Such were his words, and al-Dhahabī concurred, even though in his biographical entry in al-Mīzān he says: “Unknown,” as stated by Ibn al-Madīnī. In al-Taqrīb he is likewise listed as “unidentified.”
Al-Shawkānī (1/247) said:
“The proofs showing that the maximum period of post-partum bleeding is forty days reinforce one another through the Sunnah to the point of being sound and worthy of reliance, so adopting them is obligatory. Thus the post-partum woman must wait forty days unless she becomes pure before that, as the preceding hadiths have indicated.”
Al-Tirmidhī (258) said:
“The scholars from among the Companions of the Prophet ﷺ, the Successors, and those after them have unanimously agreed that…"