All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallAllaahu ‘alayhi wa sallam, is His Slave and Messenger.
Such a matter belongs to the Unseen and it is not subject to personal opinion. If the report proved to be authentic, then perhaps he (Al-Fudhayl) has read it in the writings of the preachers of the People of the Book. Al-Munaawi cited it in his Faydh Al-Qadeer and commented that it is about the knowledgeable person who fails to act upon the knowledge he possesses.
Another reported Hadeeth suggests the exact opposite; it reads: “Verily, Allaah, The Exalted, forgives forty sins of the knowledgeable person before He forgives one sin of the ignorant person . . .” As-Suyooti said in Al-La’aali’ Al-Masnoo‘ah that this report is fabricated; so did Al-Albaani in Dha‘eef al-Jaami‘. Even if it was assumed that the report is authentic, Al-Munaawi commented that it is about the knowledgeable person who used to act upon his knowledge and the obscene ignorant person or the one whose ignorance is not excusable.
Allaah Knows best.