Hadithi ni sahihi ikiwa kila msimulizi katika mnyororo wa upokezi ni mwenye uadilifu ('adala) na mwenye usahihi kamili wa kukumbuka [tamm al-dabbt]. Ni lazima awe na akili timamu, mwenye akili, aliyebaleghe na Muislamu wakati wa kusimulia hadithi hiyo.

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.

Uadilifu unamaanisha kwamba msimulizi ni mtu mcha Mungu [Taqwa]; yeye si mwongo na hafanyi dhambi kubwa. Ikitokea kwa namna yoyote amefanya dhambi kubwa, hutubu mara moja. Mtu wa namna hii pia huepuka dhambi ndogo kadiri awezavyo, na akizifanya, hazifanyi mara kwa mara. Mtu huyu huepuka uovu [fisq] na uchafu wa kingono [fahsh] wa aina yoyote na ana hisia wazi ya heshima. Hafanyi vitendo vinavyoonekana kuwa vya aibu au vya kudhalilisha katika jamii ya Kiislamu. Kwa mfano, hatakojoa, wala kula au kunywa akiwa amesimama hadharani.

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.

Mtu aliye thabiti kikamilifu [al-tamm al-dabbt] humaanisha kwamba msimulizi ana akili nyingi sana. Mtu huyu lazima awe na kumbukumbu imara ili kuhifadhi maneno kamili ya hadith. Pia ni muhimu kwamba maneno yakumbukwe kwa usahihi, bila kuacha shaka yoyote juu ya uhalisi wake.

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.

Ikiwa vigezo vilivyotajwa hapo juu vinatimizwa na kila mpokezi, kuanzia Sahaba hadi mpokezi wa mwisho, ndipo tu hadithi itakapokuwa sahihi. Ikiwa vigezo vyote vimetimizwa, basi hadithi hiyo ni hadithi sahihi kwa yenyewe (sahih li-dhatihi). Ikiwa mpokezi hana kumbukumbu kali, au inaripotiwa kwamba tabia yake si nzuri, lakini hadithi hiyo inathibitishwa na hadithi nyingine, basi hadithi hiyo ni hadithi nzuri (hasan).

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.

Ikiwa msimulizi ana upungufu fulani katika tabia yake, jambo linalohitaji kudhoofisha hadith, na hadith hiyo haiungwi mkono na hadith nyingine, basi huitwa hadith ya wastani [hasan].

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].

Ikiwa sharti linalofanya hadithi kuwa sahihi au hasan halipatikani kwa mmoja au zaidi ya wapokezi, basi hadithi hiyo ni dhaifu. Kwa mfano, ikiwa mpokezi hana uadilifu au si sahihi kabisa katika kukumbuka na kunukuu, na usahihi wa hadithi unaathiriwa na jambo hilo, hadithi hiyo itashushwa hadhi na kuwa hadithi dhaifu.

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.

Kuna matawi manne makuu ya hadithi. Matawi haya huamua jinsi hadithi inavyotufikia na katika hali gani inatufikia:

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

1. Hadithi Mutawatir Hadithi mutawatir ni hadithi inayopokewa kutoka kizazi kimoja hadi kingine na idadi kubwa ya wapokezi, kiasi kwamba haiwezekani kuwazia kwamba walikula njama ya kuizua.

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. Hadith maarufu [mashhur] Hadith maarufu ni hadith ambayo watu watatu au zaidi walisimulia hadith hiyo kutoka kizazi kimoja hadi kingine. Hadith hii pia inaitwa mustafid.

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. Hadithi adimu [aziz] Hadithi adimu ni hadithi ambayo watu wawili au zaidi walisimulia hadithi kutoka kizazi kimoja hadi kingine.

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. Hadithi ya pekee [gharib] Hadithi ya pekee ni hadithi ambayo mtu mmoja tu alisimulia hadithi hiyo katika mnyororo wote wa wasimulizi.

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

Istilahi zingine pia hutumika:

Other terminologies are also used:

5. Hadithi isiyo ya kawaida Hadithi ambayo ni sahihi, lakini inapingana na hadithi nyingine ambazo ni sahihi zaidi kuliko yenyewe.

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

6. Hadith Iliyohifadhiwa Hadith ambayo ni sahihi, lakini inapingana na hadith nyingine ambazo si sahihi kama yenyewe.

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

7. Hadithi iliyokataliwa [munkar] Ni hadithi dhaifu ambayo inapingana na hadithi nyingine sahihi.

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

8. Hadith Sahihi Iliyokubaliwa: Hadith yenye msimulizi thabiti, ambayo inagongana na hadith ambayo msimulizi wake ni dhaifu.