“If the source of a mursal report is sound, by its coming through another route—either with a continuous chain to the Prophet or as a mursal report transmitted by one who received it from narrators other than those of the first route—then it is authentic.” See Fath al-Mughith (1/138).
Our reply to his aforementioned statement is twofold. First, this applies to a mursal report whose rejected nature and contradiction of the authentic hadiths have not been established. The same applies, I say, to the connected report offered as corroboration for it: it is unfit to serve as corroboration, since it too is rejected, as has already been demonstrated. How can one rejected report strengthen another?!
Second, in the view of the scholars, al-Hasan’s mursal reports are like the wind, as al-Hafiz al-Iraqi said, cited by al-Suyuti in his commentary (1/204). This is because he was among those who accepted as truthful everyone who narrated to them. Ibn Sirin therefore said: “Transmit mursal reports from whomever you wish, except al-Hasan and Abu al-Aliyah, for they did not care from whom they received hadith.” Ahmad said: “There is nothing among mursal reports weaker than the mursal reports of al-Hasan and Ata ibn Abi Rabah, for they take from everyone.” I have cited both statements from al-Ala’i’s Jami al-Tahsil (pp. 44, 86, 87, and 97).
What further confirms what the scholars have said is that al-Hasan himself may narrate a hadith from a Companion without naming the one who related it to him, and then issue a legal ruling contrary to it! This indicates that he himself did not trust what he transmitted as mursal. See al-Da'ifah, hadith 342.
4 — As for his fourth hadith, he cited it from Abd al-Razzaq’s narration in al-Musannaf, from Ibn Jurayj, who said: “Nafi ibn Jubayr and others said ...” He then mentioned the hadith and said afterward: “Its chain of transmission is authentic!”