It is disliked to withhold knowledge

Narrated AbuHurayrah:

The Prophet ﷺ said: He who is asked something he knows and conceals it will have a bridle of fire put on him on the Day of Resurrection.

حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ، حَدَّثَنَا حَمَّادٌ، أَخْبَرَنَا عَلِيُّ بْنُ الْحَكَمِ، عَنْ عَطَاءٍ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ ﷺ " مَنْ سُئِلَ عَنْ عِلْمٍ فَكَتَمَهُ أَلْجَمَهُ اللَّهُ بِلِجَامٍ مِنْ نَارٍ يَوْمَ الْقِيَامَةِ " .