عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ: ((مَنْ سُئِلَ عَنْ عِلْمٍ فَكَتَمَهُ أُلْجِمَ (وَفِي رِوَايَةٍ: أُلْجَمَهُ اللَّهُ عَزَّ وَجَلَّ) بِلِجَامٍ مِنْ نَارٍ يَوْمَ الْقِيَامَةِ))
It is narrated from Sayyiduna Abu Hurairah, may Allah be pleased with him, that the Noble Prophet, peace and blessings be upon him, said: "If a person is asked about knowledge and he conceals it, then on the Day of Resurrection, Allah Almighty will bridle him with fire."