"When the circumcised parts meet, the bath becomes obligatory. I did this with the Messenger of Allah ﷺ, and we both performed the bath."
إذا جاوز الختان الختان، فقد وجب الغسل، فعلته أنا ورسول الله ﷺ فاغتسلنا.
Tirmidhi (108) and Ibn Majah (608) both narrated it through Walid bin Muslim, who said, Uzai narrated to us, who said, Abdul-Rahman bin Qasim informed us, who said, Qasim bin Muhammad informed us, from Ayesha, and he related it in similar wording. In this way Walid bin Muslim explicitly stated the transmission all the way through the chain in the version found in Ibn Majah. Tirmidhi said, hasan sahih. I say, Ibn Hibban (2/356) also graded it sahih.Tirmidhi (109) also narrated it from Hannad, who said, Waki narrated to us, from Sufyan, from Ali bin Zayd, from Saeed bin Musayab, from Ayesha, who said, the Prophet ﷺ said, "When the circumcised part passes the circumcised part, then ghusl becomes obligatory." Ali bin Zayd bin Jadan is daif. The hadith of Muslim carries the same meaning.