Because the Hadith studies show that some Hadiths are not Authentic and therefore not can be trusted you should have read my reply though i didn't even say they were
Unauthentic but it was
miss-translated by the article he copied/pasted.
A
hadith consists of two parts: its text, called
matn, and its chain of narrators, called
isnad. Comprehensive and strict criteria were separately developed for the evaluation of
matn and
isnad. The former is regarded as the internal test of
ahadith, and the latter is considered the external test.
A hadith was accepted as authentic and recorded into text only when it met both of these criteria independently.
Some little criteria's for the Isnad:
The unblemished and undisputed character of the narrator, called
rawi, was the most important consideration for the acceptance of a
hadith. As stated earlier, a new branch of
'ilm al-hadith known as
asma' ar-rijal was developed to evaluate the credibility of narrators. The following are a few of the criteria utilized for this purpose:
1. The name, nickname, title, parentage and occupation of the narrator should be known.
2. The original narrator should have stated that he heard the hadith directly from the Prophet.
3. If a narrator referred his hadith to another narrator, the two should have lived in the same period and have had the possibility of meeting each other.
4. At the time of hearing and transmitting the hadith, the narrator should have been physically and mentally capable of understanding and remembering it.
5. The narrator should have been known as a pious and virtuous person.
6. The narrator should not have been accused of having lied, given false evidence or committed a crime.
7. The narrator should not have spoken against other reliable people.
8. The narrator's religious beliefs and practices should have been known to be correct.
9. The narrator should not have carried out and practised peculiar religious beliefs of his own.
Some little criteria's for the matn:
1. The text should have been stated in plain and simple language.
2. A text in non-Arabic or couched in indecent language was rejected.
3. A text prescribing heavy punishment for minor sins or exceptionally large reward for small virtues was rejected.
4. A text which referred to actions that should have been commonly known and practised by others but were not known and practised was rejected.
5. A text contrary to the basic teachings of the Qur'an was rejected.
6. A text contrary to other
ahadith was rejected.
7. A text contrary to basic reason, logic and the known principles of human society was rejected.
8. A text inconsistent with historical facts was rejected.
9. Extreme care was taken to ensure the text was the original narration of the Prophet and not the sense of what the narrator heard. The meaning of the
hadith was accepted only when the narrator was well known for his piety and integrity of character.
10. A text derogatory to the Prophet, members of his family or his companions was rejected.
11. A text by an obscure narrator which was not known during the age of
sahabah [the Prophet's companions] or the tabi'een [those who inherited the knowledge of the
sahabah] was rejected.
Along with these generally accepted criteria, each scholar then developed and practiced his own set of specific criteria to further ensure the authenticity of each hadith. For instance, Imam al-Bukhari would not accept a hadith unless it clearly stated that narrator A had heard it from narrator B. He would not accept the general statement that A narrated through B. On this basis he did not accept a single hadith narrated through 'Uthman, even though Hasan al-Basri always stayed very close to 'Ali. Additionally, it is stated that Imam Ahmad bin Hanbal practiced each hadith before recording it in his Musnad [book or collection of hadith].
More information can be found
here