The Messenger of Allah ﷺ said, "The example of one who acquires knowledge but does not pass it on is like that of someone who hoards a treasure and spends nothing from it."
أن رسول الله ﷺ قال: مثل الذي يتعلم العلم ثم لا يحدث به، كمثل الذي يكنز الكنز فلا ينفق منه.
Tabarani related it in Awsat (689), and Ibn Abdul-Barr in Jami Bayan Ilm (774), both from the hadith of Ibn Wahb, who said, Ibn Lahia told me, from Darraj Abu Samh, from Abu Haytham and Abdul-Rahman bin Hujayra, from Abu Hurairah, who related it. Ibn Abdul-Barr did not mention Abu Haytham as a corroborator of Ibn Hujayra. Its chain is hasan because of Ibn Lahia, for Ibn Wahb's narration from him is sound, and Darraj Abu Samh's hadith from Ibn Hujayra is hasan.Munziri mentioned it in Targheeb wa Tarheeb (204) and attributed it to Tabarani's Awsat, saying, "Its chain contains Ibn Lahia." It seems he did not distinguish between the narration of the Abadila from him and that of others. Haythami stated plainly in Majma (1/164), saying, "It contains Ibn Lahia, and he is daif." This is Haythami's habitual practice regarding the narration of Ibn Lahia, for he either states plainly that he is daif or says, "It contains a known criticism," without distinguishing between the narration of the Abadila from him and that of others, so take note of that.The hadith of Abu Hurairah has other chains besides this, but what I have mentioned is the soundest of them.In similar meaning, from Jundab bin Abdullah Azdi, a companion of the Prophet ﷺ, from the Messenger of Allah ﷺ, who said, "The likeness of one who teaches people good while forgetting himself is like the lamp that gives light to people while burning itself up."Tabarani related it in Kabir (2/178) from Ahmad bin Mualla Dimashqi and Hasan bin Ali Umari, who both said, Hisham bin Ammar told us, Ali bin Sulayman Kalbi told us, Amash told me, from Abu Tamima, from Jundab, who related it. It will come in detail in the twentieth chapter.Haythami said in Majma (1/184–185), "Its narrators are trustworthy," relying on Ibn Hibban's authentication. As for Ali bin Sulayman Kalbi, Ibn Hibban rated him trustworthy and mentioned him among his trustworthy narrators (7/213), saying, "He relates unusual reports (yughrib)," and Abu Hatim said, "I see nothing wrong with his hadith."Then Haythami, in another hadith transmitted through Ali bin Sulayman Kalbi, said in Majma (6/232), "I do not know Ali bin Sulayman Kalbi." But you have already learned that Ibn Hibban mentioned him among the trustworthy narrators, and that Abu Hatim said, "I see nothing wrong with his hadith." Munziri graded it hasan in Targheeb wa Tarheeb (220), saying, "Its chain is hasan, Allah willing."It has also been related as a stopped report (mawquf) with a hasan chain. Ahmad related it in Zuhd (1127) and Abu Dawud in Zuhd (392), both from the hadith of Hammad bin Salama, who said, Jareeri told us, from Abu Sawwar Adawi, that they came to Jundab, and he mentioned something similar. Hammad bin Salama is among those who heard from Jareeri before his memory became confused.Likewise it has been related from Abu Barza as a raised report (marfu), "The likeness of one who teaches people good while forgetting himself is like the wick that gives light to people while burning itself up." Munziri mentioned it in Targheeb wa Tarheeb (218) and said, "Bazzar related it." I have not come across its chain.It has also been related from Ibn Umar as a raised report, who said, "Knowledge that is not acted upon is like a treasure that is not spent from." Ibn Abdul-Barr related it in Jami Bayan Ilm (778), saying, Ahmad bin Muhammad informed us, Ali bin Umar told us, Hasan bin Abdullah told us, Abu Yaala bin Zuhayr told us, Umar bin Yahya bin Nafi told us, Isa bin Shuayb told us, Rawh bin Qasim told us, from Ayub, from Nafi, from Ibn Umar, who related it. It contains narrators whose biographies I have not been able to trace.On this subject there is also a report from Ibn Masud as a raised report, but it is not sound, and from Ibn Abbas and Salman Farsi as stopped reports attributed to them. Refer to Jami Bayan Ilm, and Ilm by Abu Khaythama.