Depending on acceptance or rejection, hadiths are classified into two groups: maqbul (accepted) or mardud (rejected).

A maqbul hadith is one which the reliability of the narrator is accepted. It is necessary to obey a maqbul hadith.

However, a mardud hadith is one which the reliability of the narrator is denied. It is not necessary to follow a mardud hadith. Hadiths which are unclear as to whether or not they should be followed are mardud hadiths.