Aḥmad ibn ʿAbd al-Wāḥid al-Dimashqī narrated to us, Marwān—meaning Ibn Muḥammad—narrated to us, he said: Sulaymān ibn Bilāl or ʿAbd al-ʿAzīz ibn Muḥammad narrated to us—Abū Dāwūd was uncertain—Kathīr ibn Zayd narrated to us, from al-Walīd ibn Ribāḥ, from Abū Hurayrah, who said: The Messenger of Allah, peace and blessings be upon him, said: "Reconciliation is permissible among the Muslims"—Aḥmad added: "except a reconciliation that makes lawful what is forbidden or makes forbidden what is lawful." And Sulaymān ibn Dāwūd added: The Messenger of Allah, peace and blessings be upon him, said: "The Muslims are bound by their conditions."(1)

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(1) Its chain is fair (ḥasan) on account of Kathīr ibn Zayd—who is al-Aslamī—and al-Walīd ibn Ribāḥ, for both are trustworthy (ṣadūq) and of fair hadith.
It was also recorded by Aḥmad (8784), Ibn al-Jārūd (637) and (638), Ibn Ḥibbān (5091), Ibn ʿAdī in al-Kāmil 6/2088, al-Dāraquṭnī (2890), al-Ḥākim 2/49 and 4/101, and al-Bayhaqī 6/63, 64–65, and 65, via multiple paths from Kathīr ibn Zayd, from him. Some of them include the additions to which the author referred.
It was also recorded by al-Ṭaḥāwī in Sharḥ Maʿānī al-Āthār 4/90, via the path of Kathīr ibn Zayd, from him, in abbreviated form with his saying: "The Muslims are bound by their conditions."
It was also recorded by al-Dāraquṭnī (2891) and al-Ḥākim 2/50, via the path of ʿAbd Allāh ibn al-Ḥusayn al-Miṣṣīṣī, from ʿAffān, from Ḥammād ibn Zayd, from Thābit, from Abū Rāfiʿ, from Abū Hurayrah.
Al-Ḥākim said: Authentic (ṣaḥīḥ) upon the condition of the two Shaykhs, and it is known through ʿAbd Allāh ibn al-Ḥusayn al-Miṣṣīṣī, who is trustworthy. Al-Dhahabī commented on this, saying: Ibn Ḥibbān said: He steals hadith.
On this topic, there is also a hadith from Kathīr ibn ʿAbd Allāh ibn ʿAmr ibn ʿAwf al-Muzanī, from his father, from his grandfather, recorded by Ibn Mājah (2353) and al-Tirmidhī (1402). Al-Tirmidhī said: A fair and authentic hadith (ḥasan ṣaḥīḥ). We say: That is because he held a favorable view of Kathīr ibn ʿAbd Allāh al-Muzanī, following his teacher Imām al-Bukhārī, while the majority of scholars consider him weak. The most balanced statement concerning him is that he is suitable for consideration (iʿtibār) in follow-ups (mutābaʿāt) and supporting witnesses (shawāhid).
And from ʿUmar ibn al-Khaṭṭāb, as a statement stopped at him (mawqūf), in his letter to Abū Mūsā al-Ashʿarī, recorded by Wakīʿ Muḥammad ibn Khalaf in Akhbār al-Quḍāh 1/70–73, al-Dāraquṭnī (4472), and al-Bayhaqī 6/65, and its narrators are trustworthy. =