The Islamic Personality by Sheikh Taqīuddīn An-Nabahānī

Khabar Al-Aahaad is accepted if it meets the acceptance conditions of the narration (riwaayah) and the knowledge about its content (diraayah). As for the acceptance conditions of the narration; they are that, the narrator of the Hadeeth must be: Muslim, mature, sane, just, truthful, accurate in what he heard and remembering the Hadeeth since he carried (heard) it until he narrated it. The scholars of the usoul and the scholars of the Hadeeth terminology had clarified the conditions of the narration in details. And the biography of the men of the Hadeeth and their narrations had shown every narrator and what he fulfills of these qualities in details.

As for the knowledge (diraayah) conditions for accepting khabar Al Aahaad they are, that it does not contradict what is stronger (more authentic) then it, like an ayah or a mutawaatir or a mashhour Hadeeth, like what was narrated from Fatimah Bint Qays that she said: " My husband had divorced me by three then the Messenger of Allah (SAW) did not make (command) for me neither dwelling or alimony" narrated by Muslim. This Hadeeth contradicts the saying of Allah ... :ala'Ta {Let them (the divorced women) live (during the 'iddah,) where you live, from your means…) 6 Surat Al-Talaaq, Therefore it must be rejected and it is not permissible to act according to it. If the individuals report contradicts the qyas; the Hadeeth will be preferred and the qyas will be left if the illah (reasoning) of the qyas is derived, or taken from the denotation of the text, or measured on another shari'ahi illah. So the Hadeeth is preferred over the qyas in all these situations. If the comprehensive illah of the qyas came explicitly in a decisive text, like an ayah or mutawaatir Hadeeth; the action then must be according to the illah, because dictating the illah in the text is like dictating its verdict, and then the issue will be as a kind of contradiction between khabar Al-Aahaad and what is stronger then it, like an ayah or a mutawaatir Hadeeth, not contradicting with the qyas. In conclusion, if the individuals report contradicts an ayah of the Qur'aan or a mutawaatir or a mashhour Hadeeth or an illah explicitly dictated by the Qur'aan, Mutawaatir or Mashhour; the Hadeeth will be not accepted as per diraayah (after knowledge), and if it does not contradict any of those; it will be accepted. And if the Hadeeth contradicts the qyas; the Hadeeth will be accepted and the qyas will be rejected.