I say: I have found no biographical notice for Qays ibn Adam. As for his grandfather, Azhar ibn Saʿd, he was trustworthy and among the narrators relied upon by the two Shaykhs. Thus, the discrepancy may not have come from him, but rather from his grandson. The correct version is the Qurashi’s narration from al-Taymi, for it has been corroborated. Imam Ahmad (3/299) said: Yahya ibn Saʿid narrated to us, from ʿUbayd Allah ibn al-Akhnas, from Abu al-Zubayr, from Jabir, from the Prophet, peace and blessings be upon him, and he cited it.

Muslim (6/154) also narrated it through Ruh ibn ʿUbadah, who said: ʿUbayd Allah narrated to me through the same chain, with the wording: “None of you should lie on his back and then place one of his legs over the other.” He, al-Tirmidhi, Ahmad (3/349), and al-Tahawi also narrated it through al-Layth, from Abu al-Zubayr, with the wording: “He forbade wrapping oneself completely in a garment, sitting with one’s knees drawn up while wearing only a single garment, and a man raising one leg over the other while lying on his back.” Al-Tirmidhi said: “It is a good, authentic hadith.”

Muslim and Ahmad (3/297 and 322) also narrated it through Ibn Jurayj, who said: Abu al-Zubayr informed me that he heard Jabir ibn ʿAbd Allah narrating it in similar terms.

The hadith also has a supporting report from Abu Hurayrah, attributed to the Prophet, peace and blessings be upon him: “He forbade a man to lie on his back and fold one of his legs over the other.” Al-Tahawi and Ibn Hibban (1961) narrated it through Ruh ibn al-Qasim, from ʿAmr ibn Dinar, from Abu Bakr ibn Hafs, from ʿUmar ibn Saʿd ibn Abu Waqqas, from him.

I say: This is an authentic chain of transmission according to the conditions of the two Shaykhs.

Note: Al-Suyuti cited it with the wording “the back of his neck” in place of “his back.” He attributed it to al-Tirmidhi from al-Baraʾ, to Ahmad from Jabir, and to al-Bazzar from Ibn ʿAbbas. But I have found no basis for it from al-Baraʾ in al-Tirmidhi or elsewhere.

Important benefit: As for the hadith which gives as the reason for forbidding lying on one’s back that Allah Most High lay on His back after creating His creation, it is utterly rejected, as I have demonstrated in al-Daʿifah (755). Refer to it.