"The believer from among the people of faith is like the head to the body; the believer feels pain for what afflicts the people of faith just as the head feels pain for what afflicts the body." Narrated by Aḥmad (5/340), Abū Nuʿaym in "al-Ḥilyah" (8/190), and al-Quḍāʿī (3/2/2) from Muṣʿab ibn Thābit from Abū Ḥāzim from Sahl ibn Saʿd, attributed [to the Prophet]. I say: This isnād is weak, and its narrators are trustworthy except for this Muṣʿab, about whom al-Ḥāfiẓ said: "His ḥadīth is lenient." He was followed by Zuhayr ibn Muḥammad from Abū Ḥāzim, except that he said: from Abū Hurayrah, attributed [to the Prophet] in a shortened form with the wording: "The believer to the believer is like the head to the body; likewise, the believer feels pain for what afflicts the believers." Narrated by ʿAbd Allāh ibn Aḥmad in "Zawāʾid al-Zuhd" (p. 367): narrated to me by al-Walīd ibn Shujāʿ, narrated to me by al-Walīd ibn Muslim, narrated to me by Zuhayr ibn Muḥammad with it. I say: Its narrators are trustworthy, the narrators of Muslim, but this Zuhayr, about whom al-Ḥāfiẓ said in "al-Taqrīb": "The narration of the people of Shām from him is not correct, so he was weakened because of it." I say: And this ḥadīth is among them, for al-Walīd ibn Muslim is from Shām, and he is also a mudallis of tadlīs al-taswiyah. However, it is supported by the ḥadīth of al-Nuʿmān ibn Bashīr who said: The Messenger of Allāh (ṣallá Allāhu ʿalayhi wa-sallam) said: "The believers are like a single person; if his head aches, his whole body aches, and if his eye aches, his whole body aches." Narrated by Muslim (8/20), Aḥmad (4/271, 276), and Abū Nuʿaym in "al-Ḥilyah" (4/126) through two chains from him.