A hadith is authentic if every narrator in a chain of transmission is of probity adala] and thoroughly accurate [tamm al-dabbt]. He must be intelligent, sane, mature and Muslim at the time of narrating the hadith.

Probity means that the narrator is a person of Taqwa [God-fearing]; he is not a liar and does not commit major sins. If by any chance a major sin is committed, he repents immediately. Such a person also avoids minor sins as much as possible and if he does, he is not consistent upon them. This person avoids transgression [fisq] and sexual misconduct [fahsh] of any kind and has a clear sense of honor. He does not commit such acts as are looked upon as disgraceful or disreputable in Islamic society. For example, he will not urinate or eat and drink while standing in public.

A thoroughly accurate person [al-tamm al-dabbt] means that the narrator is extremely intelligent. This person must possess a strong memory so as to preserve the exact wordings of the hadith. It is also important that the words are memorized accurately, leaving no room for doubt about it being authentic.

If the aforementioned criteria are fulfilled by every narrator, from Sahaba to the last narrator, only then will a hadith be authentic. If all the requirements are fulfilled, then the hadith is a sound- in-itself narration . If a narrator is lacking in sharpness of memory or is reported to be of bad character but the hadith is corroborated by other ahadith, the hadith is a sound narration.

If the narrator is lacking in some character, which calls for a weakening of the hadith and it is not corroborated by other ahadith, it is called a fair narration [hasan].

If the criteria that makes a hadith authentic or fair is not found in one or more than one narrators, then the hadith is weak. For example, if the narrator does not possess probity or is not thoroughly accurate, and the authenticity of the hadith is affected by it, the hadith will be degraded to a weak hadith.

There are four main branches of hadith. These branches determine how and in what condition the hadith reaches us:

1. A mass-transmitted hadith [mutawatir] A mass-transmitted hadith is a hadith that is transmitted from one generation to the next in such large numbers, that one could not imagine that they conspired to forge it.

2. A well-known hadith [mashhur] A well-known narration is a hadith in which three people or more narrated a hadith from one generation to the next. This hadith is also called mustafid.

3. A rare hadith [aziz] A rare narration is a hadith in which two people or more narrated a hadith from one generation to the next.

4. A solitary hadith [gharib] A solitary hadith is a hadith in which only one person narrated a hadith throughout the transmission.

Other terminologies are also used:

5. An anomalous hadith A hadith that is authentic, but which conflicts with other ahadith that are more authentic than itself.

6. A preserved hadith A hadith which is authentic, but which conflicts with other ahadith that are less authentic than itself.

7. A declined hadith [munkar] A hadith that is weak and which conflicts with other ahadith that are authentic.

8. An accepted hadith A hadith having a strong narrator and conflicts with a hadith whose narrator is weak.

This is a summary of some of the terminologies used by the hadith masters. A more elaborate glossary and explanation of hadith terminology can be looked up in the works of the hadith masters. However the aforementioned is sufficient enough for one to understand this book and the reality of the hadith. Most of the nomenclature of the hadith masters is jargon for most people, as few will understand it.