«وَلَيْسَ شَرْطًا لِلصَّحِيحِ، خِلَافًا لِمَنْ زَعَمَهُ»
Aziz transmission is not a condition for a hadith to be sahih, contrary to those who asserted otherwise.
Solitary transmission and unreliability are not the same thing. A trustworthy narrator may be singular at a particular point while the report still meets the other requirements of authenticity.
Some scholars were understood to require multiple transmitters for soundness, but objections were raised to that claim. The proper evaluation examines honesty, precision, continuity, and relevant defects; it does not make a minimum count of two an absolute precondition of every sahih narration.
The requirement of two transmitters is reported from Abu ʿAli al-Jubbaʾi. The language of al-Hakim has also been read as inclining in that direction. Qadi Abu Bakr ibn al-ʿArabi expressly attributed such a condition to al-Bukhari in his commentary on the Sahih. These are not identical degrees of attribution: the inference from al-Hakim’s wording should not be presented as an equally explicit assertion.