A Weak Hadeeth from Mu’aadh regarding Opinion, and what is Rejected from it:
Before I finish my talk, I feel that it is necessary for me to direct the attention of the brothers in attendance to a famous hadeeth, which seldom is missing from the books on the Principles of Fiqh. I will mention it because it is weak, from the perspective of its chain of narration as well as it being in contradiction with what I spoke about in this talk, which was the lack of there being any distinction between the Qur’aan and the Sunnah when it comes to deriving Laws, and the obligation of accepting these two sources together.
Indeed it is the hadeeth of Mu’aadh bin Jabal radhi Allaahu anhu who reported that the Prophet صلى الله عليه وسلم said to him when he sent him to Yemen:
“With what will you judge by?”
He said: “By the Book of Allaah.”
He صلى الله عليه وسلم said: “And if you don’t find (the answer in) it?”
He said: “Then by the Sunnah of Allaah’s Messenger.”
He replied: “And if you don’t find (the answer in) it?”
He said: “I will strive to form my own opinion.”
So he صلى الله عليه وسلم said: “All praise be to Allaah who guided the messenger of Allaah’s Messenger to that which Allaah’s Messenger loves.”
As for the weakness of its chain, then this is not the place to discuss it now. But I clarified this exhaustively, perhaps the likes of which was not undertaken in the past, in (my book) the “Silsilah” (of weak hadeeth) I mentioned previously.  But suffice it to say now that the Ameer-ul-Mu’mineen in Hadeeth, Imaam Al-Bukhaaree, said about this hadeeth that it was “rejected.”
So having said this, it is now possible for me to begin explaining the contradiction it poses, which I stated earlier. So I say:
This hadeeth establishes a methodology of ruling for the judge, based on three stages. He is not permitted to seek a ruling from his opinion unless after he acknowledges he can’t find it in the Sunnah. Nor is he allowed to derive a ruling from the Sunnah until after he establishes he can’t find it in the Qur’aan. With respect to the opinion, this method (of deriving a ruling) is valid and correct according to all of the scholars, which is why they would say: “When the narration is mentioned, the opinion is nullified.”
However, with respect to the Sunnah, this method is not correct, because the Sunnah determines and explains the Book of Allaah. So it is obligatory for one to look for the ruling in the Sunnah, even if he thinks that it exists in the Qur’aan, based on what we stated previously. So the Sunnah with respect to the Qur’aan is not like the opinion with respect to the Sunnah. No, definitely not. Rather we must consider the Qur’aan and the Sunnah as one source, there being no distinction between them at all. This is as has been indicated in the sayings of the Prophet صلى الله عليه وسلم: “Indeed, I was given the Qur’aan and something similar to it, along with it” – meaning the Sunnah – and “They will not be separated from one another until they return to the Fountain.”
So this dividing them into categories, mentioned in the hadeeth, is not correct, because it necessitates that they are separate from one another. And this is false, as I have explained previously.
 It is found under number 885 of Silsilat-ul-Ahaadeeth ad-Da’eefah. We hope that the volume that includes it will be printed soon, in shaa Allaah.