What are the yardsticks for identifying a weak or fake Hadith?
بِسْمِ اللهِ الرَّحْمنِ الرَّحِيْم
In the name of Allah, the Most Gracious, the Most Merciful
There are many factors from il-ul-rijaal (knowledge of the efficacy and trustworthiness of narrators) to the isnaad (the quality in the chain of narrators, whether there are gaps or consistent chains to singular to multiple narrators). Then there is an issue in reconciling meanings between apparent contradictions in the Quran and Hadith that require detailed study to arrive at the reconciliation.
Suffice to say, this is not the right medium to explain the whole science, nor is it entirely possible. I recommend taking the time to study a primer in hadith nomenclature and also refer to the authentication of reliable scholars throughout our history. There is rarely a hadith that is required for day to day life that has not been studied, researched and documented. Perhaps studies in Arabic will give you greater access to those works.
As for ‘fake hadith’, what you must be referring to are fabricated [mawdoo’] hadith. These have been well documented and agreed on by the muhadditheen, and we would respond to their findings on a case by case basis.
Only Allah knows best
Written by Maulana Moinul Abu Hamza
Checked and approved by Mufti Mohammed Tosir Miah
Darul Ifta Birmingham