It is not permissible to establish a legal ruling based on a weak hadith, and clarification that a weak hadith only yields the weaker form of conjecture, and mention of the categories of conjecture.

The Shaykh : Add to this, if you remember, the consensus of the scholars of the Muslims that it is not permissible to act upon a weak hadith in matters of rulings, or that it is not permissible to establish a legal ruling, even at its lowest level, which is the recommended practice, based on a weak hadith. Why do they say this? Because they also agreed that a weak hadith does not yield anything but the weaker form of conjecture. And the weaker form of conjecture is what Allah (Blessed and Exalted is He) forbade the polytheists from following, when He said: . And our Lord (Blessed and Exalted is He) said in evaluating this conjecture: . And the Messenger (peace be upon him) confirmed this by saying: . So, this hadith that came with a weak chain of narration yields conjecture, and we have been forbidden in these definitive texts from resorting to it and acting upon it absolutely.

The questioner : The same scholars said: A hadith of the singular category yields conjecture... it yields conjecture...

The Shaykh : Pardon me, for some reason I said that a weak hadith yields the weaker form of conjecture. What you are attributing to the scholars is not conjecture, but rather the opposite of that; that is the stronger form of conjecture. The scholars of the... as you say, said that a hadith of the singular category yields conjecture, but when they use the term conjecture, they do not mean the conjecture that Allah condemned and criticized, but rather the conjecture that is obligatory upon us by the Shari'ah to act upon, and its description is "the stronger form of conjecture." So, we can now say that conjecture is divided into three categories—no, I am not guessing: certainty, the stronger form of conjecture, and the weaker form of conjecture.
So, the weaker form of conjecture does not enter into the Shari'ah of Islam—and praise be to Allah—absolutely. As for the stronger form of conjecture, it is obligatory to act upon it, whether in rulings or in creed, as long as it comes through an authentic hadith. And the other form of conjecture, which is certainty, there is no doubt that this is the best thing to which the mind or heart of a person can find rest. And in this sense came the saying of Allah (Blessed and Exalted is He), narrating the words of the believer: . So, what does "I thought" mean here? Certainty.

The questioner : I believed.

The Shaykh : Yes?

The questioner : I believed.

The Shaykh : So, conjecture—Professor—does not always mean the weaker form of conjecture, nor does it always mean the stronger form of conjecture. Sometimes it means certainty, as you heard in the noble verse, and sometimes it means the stronger form of conjecture. And upon this are all the rulings of the Shari'ah. That is, the judge here, when he rules for so-and-so against so-and-so, or rules to cut off the head of so-and-so, whether he has certainty in this case or he has the stronger form of conjecture... the stronger form of conjecture is the basis upon which the rulings of the Shari'ah are established. As for the weaker form of conjecture, it is absolutely not permissible to act upon it. So, there is a difference between the weaker form of conjecture and the stronger form of conjecture. And the stronger form of conjecture is divided into certainty and the stronger form of conjecture.

Eid Abbasi : Certainty, now they think that there is...

The Shaykh : A lot, yes.
So, the point—our brothers—is that this detail, and linking rulings that differ according to the degree of establishment of the hadith in the mind of a person, this is something that no one who knows the development of these matters with the development of the eras can accept.