The Prophet ﷺ missed Kaab and asked about him. The people said, "He is ill."So he set out on foot until he came to him. When he entered upon him, he said, "Receive good news, Kaab."His mother said, "May Paradise be a pleasant reward for you, Kaab."The Prophet ﷺ asked, "Who is this woman swearing oaths about what Allah will do?"Someone replied, "She is my mother, Messenger of Allah."He said, "Umm Kaab, how do you know? Perhaps Kaab spoke of what did not concern him, or withheld what would not have impoverished him."
أن النبي ﷺ فقد كعبا فسأل عنه فقالوا: مريض، فخرج يمشي حتى أتاه، فلما دخل عليه قال: أبشر يا كعب، فقالت أمه: هنيئا لك الجنة يا كعب فقال: من هذه المتألية على الله؟ قال: هي أمي يا رسول الله فقال: وما يدريك يا أم كعب؟ لعل كعبا قال ما لا يعنيه، أو منع ما لا يغنيه.
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Ibn Abu Dunya narrated it in al-Samt (110), and Tabarani in al-Awsat (7157), both through the route of Ahmad bin Isa al-Misri, who said, Dimam bin Ismail al-Iskandarani told us, Yazid bin Abu Habib and Musa bin Wardan told me, from Kaab bin Ujra, who said, then he mentioned it.Tabarani said, "No one narrated from Kaab except Musa bin Wardan, and Dimam alone transmitted it." That is, no one narrated it with a connected chain from Kaab except Musa bin Wardan, while the narration of Yazid bin Abu Habib is disconnected, since he did not meet Kaab. Its chain is hasan because of Musa bin Wardan, for his hadith is hasan when it does not contradict others.Haythami said in al-Majmu (10/314), "Tabarani narrated it in al-Awsat, and its chain is good."His statement, "he missed Kaab," refers to Kaab bin Malik bin Abu Kaab al-Ansari.