One of the tools that will be used to determine and gloss the meaning of the Qur'an correctly is to adopt an accurate approach in order to recognize the revelation atmosphere and the narratives of asbab al-nuzul (the reasons of revelation) and analyzing them correctly. Most of our acceptances and rejections are based on the narratives of asbab al-nuzul. Viewpoints are propounded that these narrations should be evaluated according to the content of the Qur'an, the hadith method, the narrative patterns, and the harmony with the prophetic biography. For example, although it is accepted that Ka'b b. Ashraf, who is one of the Jews of Medina, was killed after Badr, his name is narrated in glosses regarding the revealed verses long after that. This contradictory situation requires that the compliance of the asbab alnuzul narratives should be examined with the facts. In this paper, we tried to evaluate the information in the sources analytically by discussing the aforementioned issues based on the sample of Ka`b b. Ashraf. As a conclusion, we determined that his name was mentioned in the asbab al-nuzul of many verses revealed after his death because the intention of the predecessor wasn't understood correctly and diachronic consistency wasn't paid enough attention.