who said: Kathīr ibn Zayd narrated to us, from al-Walīd ibn Rabāh, from Abū Hurayra, who said: The Messenger of Allah—may Allah bless him and grant him peace—said: “A settlement is permissible among Muslims, except one that makes lawful what is forbidden or forbids what is lawful. Muslims are bound by their conditions.” Regarding Kathīr ibn Zayd, Yahyā ibn Ma'īn said in one report, “He is trustworthy,” but declared him weak in another.

Al-Tirmidhī and al-Bazzār also narrated, through Kathīr ibn Abd Allāh ibn Amr ibn Awf al-Muzanī, from his father, from his grandfather, that the Messenger of Allah—may Allah bless him and grant him peace—said: “A settlement is permissible among Muslims, except one that forbids what is lawful or makes lawful what is forbidden. [Muslims are bound by their conditions, except a condition that makes lawful what is forbidden or forbids what is lawful.]” Al-Tirmidhī said: “This is a good and authentic hadith.” Ibn Mājah narrated its first wording. However, the hadith authorities generally declared Kathīr ibn Amr weak. Ahmad struck out his hadith in the Musnad and did not narrate it. Perhaps al-Tirmidhī graded it authentic because it was narrated through several routes.

Abū Bakr al-Bazzār also narrated from Muhammad ibn Abd al-Rahmān al-Baylamānī, from his father, from Ibn Umar, who said: The Messenger of Allah—may Allah bless him and grant him peace—said: “People are bound by their conditions insofar as they accord with the truth.” Although any one of these chains of transmission is weak, their convergence through multiple routes causes them to reinforce one another.

It is this meaning that is attested by the Book and the Sunnah, and it is the essence of