from Jubayr ibn Nufayr, from al-Nawwās ibn Samʿān, who said:
The Messenger of Allah (peace and blessings be upon him) said, “The gravest act of betrayal is that you speak to your brother about something, he believes you, while you are lying to him.” (1)
Yazīd: declared reliable.
I read this to ʿĪsā ibn Yaḥyā; Manṣūr ibn Sanad informed us; Abū Ṭāhir the ḥāfiẓ informed us; Abū Bakr Aḥmad ibn Muḥammad ibn Aḥmad the ḥāfiẓ informed us; ʿUmar ibn ʿAbd Allāh ibn al-Haytham the preacher informed us in the year 417 AH; Abū al-Qāsim al-Ṭabarānī narrated to us; ʿAbd al-Wārith ibn Ibrāhīm narrated to us; ʿAmmār ibn Hārūn narrated to us; ʿUmar ibn Hārūn al-Balkhī narrated to us; Thawr ibn Yazīd narrated to us, from Makḥūl, from al-Nawwās ibn Samʿān al-Kilābī, who said:
The Messenger of Allah (peace and blessings be upon him) said, “O Allah, bless my ummah in their early mornings.” (2)
(1) The chain of transmission is weak because of the unreliability of ʿUmar b. Harun. Ahmad, 4/183, also records it through ʿUmar b. Harun with the same isnad. Thawr is Thawr b. Yazid al-Himsi, who is trustworthy and precise.
In the printed Musnad the wording appears as “Thawr b. Yazid from Shurayh,” which is incorrect; the correct reading is “Thawr from Yazid b. Shurayh.” Abu Dawud (4971) in the Book of Manners, chapter “on indirect language,” and al-Bukhari in al-Adab al-mufrad (393) transmit it through Baqiyya b. al-Walid → Dabara b. Malik al-Hadrami → his father → ʿAbd al-Rahman b. Jubayr b. Nufayr → his father → Sufyan b. Asid al-Hadrami. This chain is weak: Baqiyya b. al-Walid was a mudallis and reports with ʿanʿana; Dabara is unknown, as is his father.
(2) The isnad is weak owing to ʿUmar b. Harun. Al-Haythami (Majmaʿ, 4/62) cites it from al-Tabarani’s al-Kabir and likewise deems it weak for the same reason. Still, the content of the hadith is sound because of its many supporting chains: Ahmad 3/416, 432; 4/384, 390, 391; Abu Dawud (2606); al-Tirmidhi (1212); and Ibn Majah (2236) transmit it from Sakhr al-Ghamidi. ʿAbd Allah b. Imam Ahmad includes it in Zawaʾid al-Musnad (1319, 1322, 1328) from ʿAli; Ibn Majah (2237, 2238) records it from Abu Hurayra and from Ibn ʿUmar. Additional corroborating reports exist from Ibn Masʿud (with Abu Yaʿla and al-Tabarani), from ʿAbd Allah b. Salam (idem), from Anas (al-Bazzar), from Ibn ʿAbbas (al-Bazzar and al-Tabarani), from ʿAʾisha (idem), and others; see Majmaʿ, 4/61-62.