«الَّذِي لَمْ يَأْخُذْ عَنِ الْإِسْرَائِيلِيَّاتِ»
A Companion not known to draw from Israelite accounts.
This qualification matters because details about earlier prophets, ancient nations, and certain unseen matters could also circulate through the People of the Book. If that is a plausible source, the mere fact that a report discusses the unseen does not conclusively establish Prophetic origin.
Critical procedure: consider the transmitter’s sources, the content, the possibility of ijtihād, and any corroborating indications. One must neither claim Israelite sourcing without evidence nor overlook a known alternative source when deciding the report’s attribution.