in al-Mīzān:

“Ibn ‘Uyayna and Ibn Ma‘īn declared him trustworthy. Ibn ‘Adī said: ‘I hope there is nothing objectionable about him.’ Al-Nasā’ī said: ‘He is weak.’ ‘Uthmān ibn Sa‘īd likewise declared him weak. Abū ‘Abd Allah al-Hākim said: ‘Fudayl ibn Marzūq does not meet the criteria for inclusion in an authentic collection. Muslim was criticized for including him in the Sahīh.’ Ibn Hibbān said: ‘His hadiths are highly objectionable. He was among those who made errors when narrating from trustworthy authorities, and he narrated fabricated reports from ‘Atiyya.’ I say: ‘Atiyya is weaker than he is. Ibn ‘Adī said: ‘In my view, when his narration agrees with those of trustworthy narrators, it may be cited as proof.’”

Al-Hāfiz said in al-Taqrīb: “Generally truthful, but prone to error.”

I say: At best, the hadith of a narrator such as this is acceptable; it cannot be deemed authentic. Al-Hāfiz Ibn Rajab indicated this in Commentary on the Forty Hadiths, saying (p. 70):

“Fudayl ibn Marzūq is a trustworthy narrator of middling rank. Muslim narrated from him, but al-Bukhārī did not.”

18—(And he says: “Whoever amasses wealth unlawfully and then gives it in charity will receive no reward for it, while its sinful burden will remain upon him.” Narrated by Ibn Khuzayma, Ibn Hibbān, and al-Hākim from Abū Hurayra). p. 34

Weak. Ibn Hibbān (797, 836—Mawārid) and al-Hākim (1/390) narrated it through Darrāj Abū al-Samh, from Ibn Hujayra the Elder al-Khawlānī, from Abū Hurayra. Al-Hākim said:

“Authentic.”

Al-Dhahabī concurred with him. This was hasty and showed insufficient scrutiny on his part. Al-Hākim had elsewhere narrated another hadith of Darrāj (1/212) and deemed it authentic, whereupon al-Dhahabī took him to task, saying: