Hilal reported that he saw the Prophet ﷺ undress for entering the state of ihram and perform a full bath.
أنه رأى النبي ﷺ تجرد لإهلاله واغتسل.
Tirmidhi (830) narrated it from Abdullah bin Abu Ziyad, who said, Abdullah bin Yaqub Madani narrated to us, from Ibn Abu Zinad, from his father, from Kharija bin Zayd bin Thabit, from his father, and he mentioned it.Tirmidhi said, this is a hasan gharib hadith.I say, it is as he said, for its chain contains Ibn Abu Zinad, who is Abdul-Rahman, and as stated in Taqrib, "He was truthful, but his memory changed after he came to Baghdad, and he was a jurist." However, the narrator from him, Abdullah bin Yaqub Madani, is "of unknown status" as stated in Taqrib, except that he has a corroborating narration, as reported by Daraqutni (2434), and from him Bayhaqi (5/32), who said, Yahya bin Saeed narrated to us, Yahya bin Khalid Abu Sulayman Makhzumi narrated to us, Abu Ghaziya Muhammad bin Musa narrated to me, from Abdul-Rahman bin Abu Zinad, with his chain, similarly.Bayhaqi said, "Abu Ghaziya is not strong."Then Bayhaqi narrated it through another route, from Aswad bin Amir Shazan, from Abdul-Rahman bin Abu Zinad, with his chain, similarly. This is another corroboration for Abdullah bin Yaqub Madani. Aswad bin Amir Shami, nicknamed Shazan, is thiqah among the narrators of the Jamaah.With this corroboration, the hadith becomes hasan, and the only reason Tirmidhi did not grade it sahih is the criticism directed at Abdul-Rahman bin Abu Zinad.