I heard the Messenger of Allah ﷺ say, "Whoever is asked about knowledge and conceals it will be bridled on the Day of Resurrection with a bridle of fire."
حدثنا أحمد بن الأزهر حدثنا الهيثم بن جميل حدثني عمر بن سليم حدثنا يوسف بن إبراهيم قال سمعت
سمعت رسول الله ﷺ يقول من سئل عن علم فكتمه ألجم يوم القيامة بلجام من نار
[Hasan] Busiri said, this isnad is daif, containing Yusuf bin Ibrahim. Ibn Hibban said, he narrated from Anas what is not from his hadith, and it is not permissible to narrate from him. See also number 266.