The evidence for the ‘aqīdah must be definite and of unquestionable authenticity. That is why the isolated report (khabar al-ahad) is not fit to be an evidence for ‘aqīdah even if it is a sound hadīth (hadīth Sahih) in its meaning and transmission. As for the Sharī’ah rule, it suffices for its evidence to be speculative (zanni). Therefore, just as the mutawatir hadīth suffices as an evidence for the Sharī’ah rule, likewise the isolated report (khabar al-ahad) suffices as an evidence for the Sharī’ah rule. However, the khabar al-ahad which is suitable to be an evidence for the Sharī’ah rule is the hadīth Sahih and hadīth hasan. As for the weak hadīth (hadīth da'eef) it cannot serve as a Sharī’ah evidence at all. Anyone who educes it he will not be considered to have educed a Sharī’ah evidence. However the consideration of a hadīth as Sahih (sound) or hasan (good) is according to the one who educes it, if he is qualified to understand the hadīth, which may not be so for the rest of the muhadithin. That is because there are transmitters who are trustworthy (thiqa) for some muhadithin but not so for some other muhaddithin, or are considered to be from the obscure (majhul) for some muhaddithin and well known for others. There are ahadīth which are not sound from one line of transmission but are from another and there are lines of transmission which are correct for some but not for others. And there are ahadīth which are not recognised by some muhaddithin and are impugned by them but they are recognised by other muhaddithin who advance them as proof. And there are ahadīth which some of the Ahl al-hadīth discredited but fuqaha in general accepted them and used then a proof. People's adherence to the consideration of a hadīth as Sahih or hasan according to a particular opinion or all of the opinions constitutes an incorrect adherence and contradicts the reality of the hadīth. Nor is it allowed to hastily accept a hadīth without due consideration to its authenticity, likewise it is not allowed to hastily discredit a hadīth and reject it merely because one of the muhaddithin has questioned the probity of a transmitter due to the possibility that it might be acceptable with another transmitter. And one should not reject a hadīth purely because one muhaddith has rejected it because of the possibility that it might be accepted by another muhaddith or reject it because the muhaddithin (in general) have rejected it because of the possibility that it might have been used as proof by the imams and general body of fuqaha (jurists). One should not be rash in discrediting or rejecting a hadīth except if its transmitter is known by all to be disparaged or the hadīth is rejected by everyone or no one advanced it as a proof except some of the fuqaha who lacked knowledge of the hadīth. It is then that the hadīth is discredited and rejected. One should be careful and give it thought before one calls a hadīth into question or reject it. Anyone who scrutinises the transmitters and and ahadīth he will find many differences regarding them between the muhaddithin. And the examples are many. For example: Abu Dawud narrated on the authority of 'Amr ibn Shu'ayb who narrated from his father, who narrated from his grandfather that the Messenger of Allah  said:

The transmitter of this hadīth is 'Amr ibn Shu'ayb and ‘Amr ibn Shu'ayb narrated from his father and from his grandfather line of transmission is famous. Despite that many have used his hadīth as proof and others have rejected it. Tirmidhi said: Muhammad ibn Isma'il said: I saw Ahmad and Ishaq (and he mentioned others) who used the hadīth of 'Amr ibn Shu'ayb as proof. He said:

'Amr ibn Shu'ayb heard ahadīth from 'Abd Allah ibn 'Umar. Abu 'Isa said: whoever spoke about the hadīth of 'Amr ibn Shu'ayb branded him as weak because he used to quote ahadīth from his grandfathers books as if they considered him not to have heard these ahadīth directly from his grandfather. 'Ali ibn Abi 'Abd Allah al-Madini said that Yahya ibn Sa'id said: The hadīth of 'Amr ibn Shu'ayb for us is unfounded. Despite this, if someone establishes a Sharī’ah rule with the hadīth of'Amr ibn Shu'ayb, his evidence will be considered a Sharī’ah evidence because 'Amr ibn Shu'ayb is one of those people whose hadīth the muhaddithin cite as an evidence. For example, in al-Darqutni, al-Hasan narrated on the authority of 'Ubada and Anas ibn Malik that the Prophet  said:

In the isnād of this hadīth there is al-Rabi' ibn Subayh, Abu Zur'a has verified him as trustworthy but another group has weakened him. Al-Bazzar has recorded this hadīth also and it is considered as a sound (Sahih) hadīth. When someone educes this hadīth or a hadīth whose isnād contains al Rabi' ibn Subayh, then he has educed a Sharī’ah evidence because this hadīth is sound according to one group (of rijal scholars), and because al-Rabi' is trustworthy (thiqa) for another group (of rijal critics). It should not be said here that when a person is declared trustworthy and also disparaged that the invalidation (jarh) takes precedence over the attestation of reliabilitiess since that can only be when they are reported about one person according to the view of one person. As for when they are reported by two persons and one considers it as an impugnation (ta'n) and the other does not, then it is allowed. It is from here that some scholars have recognised certain transmitters (as reliable) and others have not.

For example: Abu Dawud, Ahmad, al-Nasa'i, Ibn Maja and al-Tirmidhi narrated on the authority of Abu Hurairah that:

Tirmidhi has reported that Bukhari verified the soundness of this hadīth and Ibn 'Abd al-Barr judged it as sound because the '‘Ulamā have accepted it and it has been authenticated by Ibn al Munzir. Ibn al-Asir said in the Sharh al-Musnad: This hadīth is Sahih and mashhur, the imams recorded it in their books. They used it as proof, its transmitters are trustworthy. Shafi'i said that there is a transmitter in the isnād (chain) of this hadīth 'whom I do not know'. Ibn Daqiq al-'Ayyid mentioned the aspects of justification by which he justifies this hadīth. One of them is the lack of knowledge surrounding Sa'id ibn Salama and al-Mughira ibn Abi Burda, both of whom are mentioned in the isnād, whereas some muhaddithin have said these two transmitters are indeed known. Abu Dawud said al-Mughira is known and his reliability is attested by al-Nasa'i. Ibn 'Abd al-Hakam said the people of Africa gathered around him (al-Mughira) after the murder of yazid bin Abi Muslim and said that he is unknown. Al-Hafiz said: it should be known from this mistake that the one who assumed that he (i.e AlMughira) is Majhul is not correct. As for Sa’id bin Salama, Safwan bin Salim followed him in his narration from al-Julah bin Kathir. So if anybody used this hadith as an evidence or he used the report of al-Mughira and Said as a proof then he would have used a Shar'i evidence. This is because this Hadith is considered valid and these two transmitters are considered reliable in view of some Muhaddithin.

For example: Ahmad narrated that Sa'ad ibn Abi Waqqas said:

This hadīth has been authenticated by al-Tirmidhi and a group of people impugned it, from them are Tahawi, Tabari, Ibn Hazm and Abdul Haqq because in its isnad there is Zayd abu ‘Ayaash and he is Majhul. It is said in ‘at-talkhees wal jawab’ that Darqutni said that he is trustworthy (i.e Zayd abu ‘ayaash) and Munziri said, two trustworthy people have narrated from him and Malik relied on him despite the severe criticism. So if some one takes this Hadith as a Sharī’ah evidence or takes as an evidence a hadith which has Zayd Abu ‘Ayaash, then he would have educed from a Shari’ evidence.

For example: Ahmad & Abu Dawud narrated that Abu Sa'id al-Khudri said: I heard the Messenger of Allah  say:

This hadith has ‘Ikrima ‘Amaar al’Ajaily , Muslim has accepted it in his Sahih (i.e Sahih Muslim), although some of the Huffaz have weakened the ahadith of ‘Ikrima who narrated from Yahya ibn Kathir whereas Muslim reported ahadith on the authority of Yahya and Bukhari also witnessed it. Therefore, if someone educed a rule from this hadith or from a hadith which has ‘Ikrima then he would have educed from a Shari’ evidence despite the existence of impugnation of the hadith and that of ‘Ikrima. For example: Ahmad, Abu Dawud, al-Nasa'i, Ibn Maja and al-Tirmidhi narrated on the authority of Yusra bint Safwan that the Prophet  said:

This hadīth has been recorded by Malik, al-Shafi'i, Ibn Khuzayma, Ibn Hayyan, al-Hakim and Ibn al-Jarud. Abu dawud said: I said to Ahmad: the hadīth of Busra is not sound. He said: No, it is sound. Bayhaqi said: Even though the shaykhayn (i.e, two Shaykhs, Bukhari and Muslim) did not record this hadīth due to disagreements about whether the sama' (hearing of hadīth) took place from 'Urwa or Marwan but they have used all of its transmitters (elsewhere as reliable transmitters). If someone uses this hadīth as proof, it is Sharī’ah evidence even if Bukhari and Muslim did not record it. If a hadīth is not advanced as proof by Bukhari and Muslim then that does not amount as a denigration of the hadīth.

For example: The hadīth:

and the hadīth

The general body of fuqaha have used both the ahadīth and some have contested their authenticity. If one of them used these as proof then he is considered to have educed a Sharī’ah evidence.

Thus many of the differences in hadīth, transmitters and the lines of transmission between muhaddithin becomes clear. Many disagreements between muhaddthin, the general fuqaha and certain mujtahidin do take place. When a hadīth is rejected due to this disagreement then many ahadīth considered to be Sahih or hasan have been rejected. And many Sharī’ah evidences are eliminated and this is not allowed. This is why a hadīth should not be rejected except for the correct reason, which might be recognised by the majority of the muhaddithin or it might not satisfy the necessary conditions for the Sahih and hasan hadīth. It is permitted to educe a hadīth when it is recognised by some of the muhaddithin and it fulfils the conditions of the hadīth Sahih and hasan. It is considered as a Sharī’ah evidence and the extracted hukm is a Sharī’ah rule.