Hadith report, the scale of the report's transmission, the routes through which the report was transmitted, and the individual narrators involved in its transmission. On the basis of these criteria, various classifications were devised for hadith. The earliest comprehensive work in hadith studies was Abu Muhammad al-Ramahurmuzi's "al-Muhaddith al-Fasil", while another significant work was al-Hakim al-Naysaburi's "Ma‘rifat ‘ulum al-hadith". Ibn al-Salah's "ʻUlum al-hadith" is considered the standard classical reference on hadith studies. By means of hadith terminology, hadith are categorized as "ṣaḥīḥ" (sound, authentic), "ḍaʿīf" (weak), or "mawḍūʿ" (fabricated). Other classifications used also include: "ḥasan" (good), which refers to an otherwise
Hadith of the Ark covered with dark clouds that the only, unique way of salvation is boarding this Ark (safinah). Al-Samhudi states: The salvation is the aspect of resemblance of "Ahl al-Bayt" to Noah's ark by the Prophet. As a result, hadith implies that to be grateful to "Ahl al-Bayt" by their gratitude, appreciation and sanctity. Everyone behave in this way, he is survived from the darkness of enmity and he is grateful; otherwise he is drowned in the sea of disbelief and the punishment of hell is urgent for him. Hadith of the Ark The Hadith of the Ark () is a tradition