Hadith and Hadith Sciences
Core vocabulary
Master the terminology of Hadith science: isnad (chain), matn (text), sahabi (Companion), tabi'i (Successor). Know the difference between Hadith, Sunnah, Athar, and Khabar.
Classification by authenticity
Separate Sahih (sound), Hasan (good), Da'if (weak), and Mawdu' (fabricated). Know the five conditions of a Sahih Hadith: continuous chain, upright narrators, precise memory, no irregularity (shudhudh), and no hidden defect ('illah). The trap is treating Hasan as a synonym for Da'if; it is acceptable evidence, though below Sahih.
Classification by chain
Know Mutawatir (many independent chains, giving certainty) versus Ahad (fewer chains, giving probable knowledge). Within Ahad: Mashhur, 'Aziz, and Gharib. Also know Marfu' (traced to the Prophet), Mawquf (traced to a Companion), and Maqtu' (traced to a Successor).
The science of narrator criticism
Understand jarh wa ta'dil (disparagement and validation) and why the chain matters more than the text in authentication.
Worked rule of thumb
When asked to grade a Hadith, check the chain first: Is it continuous? Are the narrators reliable? Is there a hidden defect? If the chain breaks, the Hadith is munqati' or mursal and generally weak. A Hadith with a single narrator at every level is Gharib; with two, 'Aziz; with three or more, Mashhur.