عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللّهِ صَلَّى اللّهُ عَلَيْهِ وَسَلَّمَ: «مَنْ سُئِلَ عَنْ عِلْمٍ فَكَتَمَهُ أُلْجِمَ يَوْمَ الْقِيَامَةِ بِلِجامٍ مِنْ نَارٍ» رَوَاهُ أَبُو دَاوُودَ وَالتِّرْمِذِيُّ، وقَالَ: حَدِيثٌ حَسَنٌ.
Abu Hurayrah (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) said: "Whoever is asked about knowledge and conceals it will be bridled on the Day of Resurrection with a bridle of fire." Reported by Abu Dawud and al-Tirmidhi, who said: a hasan (good) hadith.
الشرح · explanation
عِلم: أي مُحتاج إليه ويلزمه تعليمه. كتمه: لم يبينه. ألجم: هو ما يوضع في فم الفرس، والمراد: أنّ من كتم العلم كأنّه ألجم نفسه بلجام، فكان جزاؤه من جنس فعله.
"Knowledge": that is, knowledge that is needed and which he is obliged to teach. "Conceals it": does not make it clear. "Bridled" (uljima): the bridle is what is placed in the mouth of a horse; what is meant is that whoever conceals knowledge is as though he has bridled himself with a bridle, so his recompense was of the same kind as his deed.
الدروس · lessons
كتمان العلم من الكبائر التي يستحق عليها الوعيد الشديد والعقاب الأليم. وجوب تبليغ العلم إذا كان متعينًا عليه، وخاصة ما يتعلق بأمر الدين.
Concealing knowledge is among the major sins deserving of severe threat and painful punishment. The obligation of conveying knowledge when it is specifically incumbent upon a person, especially what relates to the affair of the religion.