THE CLASSIFICATION OF HADITH: According to the manner in which the hadith is reported

Mudallas hadith & Tadlis

Different ways of reporting, e.g. (he narrated to us), (he informed us), (I heard), and (on the authority of) are used by the reporters of hadith. The first three indicate that the reporter personally heard from his shaikh, whereas the fourth mode can denote either hearing in person or through another reporter.

A mudallas ("concealed") hadith is one which is weak due to the uncertainty caused by tadlis. Tadlis (concealing) refers to an isnad where a reporter has concealed the identity of his shaikh. Ibn al-Salah describes two types of tadlis:

1. tadlis al-isnad. A person reports from his shaikh whom he met, what he did not hear from him, or from a contemporary of his whom he did not meet, in such a way as to create the impression that he heard the hadith in person. A mudallis (one who practises tadlis) here usually uses the mode ("on the authority of") or ("he said") to conceal the truth about the isnad.
2. tadlis al-shuyukh. The reporter does mention his shaikh by name, but uses a less well-known name, by-name, nickname etc., in order not to disclose his shaikh's identity.38

   Al-'Iraqi (d. 806), in his notes on Muqaddimah Ibn al-Salah, adds a third type of tadlis:

3. tadlis al-taswiyyah. To explain it, let us assume an isnad which contains a trustworthy shaikh reporting from a weak authority, who in turn reports from another trustworthy shaikh. Now, the reporter of this isnad omits the intermediate weak authority, leaving it apparently consisting of reliable authorities. He plainly shows that he heard it from his shaikh but he uses the mode "on the authority of" to link his immediate shaikh with the next trustworthy one. To an average student, this isnad seems free of any doubt or discrepancy. This is known to have been practised by Baqiyyah b. al-Walid, Walid b. Muslim, al-A'mash and al- Thauri. It is said to be the worst among the three kinds of tadlis.39

Ibn Hajar classifies those who practised tadlis into five categories in his essay Tabaqat al- Mudallisin:

	Those who are known to do it occasionally, such as Yahya b. Sa'id al-Ansari.
	Those who are accepted by the traditionists, either because of their good reputation and relatively few cases of tadlis, e.g. Sufyan al-Thauri (d. 161), or because they reported from authentic authorities only, e.g. Sufyan Ibn 'Uyainah (d. 198).
	Those who practised it a great deal, and the traditionists have accepted such ahadith from them which were reported with a clear mention of hearing directly. Among these are Abu 'l- Zubair al-Makki, whose ahadith narrated from the Companion Jabir b. 'Abdullah have been collected in Sahih Muslim. Opinions differ regarding whether they are acceptable or not.
	Similar to the previous category, but the traditionists agree that their ahadith are to be rejected unless they clearly admit of their hearing, such as by saying "I heard"; an example of this category is Baqiyyah b. al- Walid.
	Those who are disparaged due to another reason apart from tadlis; their ahadith are rejected, even though they admit of hearing them directly. Exempted from them are reporters such as Ibn Lahi'ah, the famous Egyptian judge, whose weakness is found to be of a lesser degree. Ibn Hajar gives the names of 152 such reporters.40

Tadlis, especially of those in the last three categories, is so disliked that Shu'bah (d. 170) said, "Tadlis is the brother of lying" and "To commit adultery is more favourable to me than to report by way of Tadlis."41

Musalsal

A musalsal (uniformly-linked) isnad is one in which all the reporters, as well as the Prophet (may Allah bless him and grant him peace), use the same mode of transmission such as 'an, haddathana, etc., repeat any other additional statement or remark, or act in a particular manner while narrating the hadith.

Al-Hakim gives eight examples of such isnads, each having a different characteristic repeated feature:

	use of the phrase sami'tu (I heard);
	the expression "stand and pour water for me so that I may illustrate the way my shaikh performed ablution";
	haddathana (he narrated to us);
	amarani (he commanded me);
	holding one's beard;
	illustrating by counting on five fingers;
	the expression "I testify that ..."; and
	interlocking the fingers.42

Knowledge of musalsal helps in discounting the possibility of tadlis.