In the books, we read some Isra'iliyyat (isrāʾīliyyāt; narratives of Jewish origin), and we see that these are unfounded passages and doctrines that are not Islamic. These were introduced by Jews who either insincerely affiliated themselves with Islam or, though sincere, still had minds attached to the lines of Judaism. They transmitted these passages from the books of their prophets, which had been subject to distortion and alteration. Some Muslims, mistakenly thinking them to be true, accepted them.
(Praise be to Allah) the Exalted, Who has enabled Muslim scholars to cleanse these isrāʾīliyyāt and to warn Muslims of their harm, especially to understand and explain those matters that damage creed (ʿaqīda). For example, stories such as Job (Ayyūb, peace be upon him) falling ill and worms infesting his body, or attributing sin to some of the prophets (anbiyāʾ), or that David (Dāwūd, peace be upon him) fell in love with the wife of one of his soldiers and, for this reason, sent her husband to war in certain places to have him killed, and after his death, took the woman and married her. Likewise, concerning Joseph (Yūsuf, peace be upon him), that he plotted lewdly and shamefully against the family of the Aziz. Or, by embellishing such stories, they fabricated tales and narratives unworthy of the ranks of the Noble Messenger (the Messenger of God, peace be upon him). Yet, Allah the Exalted has protected the prophets from all evil and lewdness. (They are infallible.)
It is obligatory for every Muslim to abandon these isrāʾīliyyāt and to trust in Islamic, authentic, and well-known sources.