Surat Yusuf (54-55)

{وَقَالَ الْمَلِكُ ائْتُونِي بِهِ أَسْتَخْلِصْهُ لِنَفْسِي فَلَمَّا كَلَّمَهُ قَالَ إِنَّكَ الْيَوْمَ لَدَيْنَا مِكِينٌ أَمِينٌ} (يوسف : 54 )

54- When the king became sure of Yusuf's innocence and integrity, he said: Bring him to be one of my counselors.

So, when he spoke to him and knew his merit and status, he said to him: You have a great status and high rank, and you shall be entrusted with great matters.

{قَالَ اجْعَلْنِي عَلَى خَزَآئِنِ الأَرْضِ إِنِّي حَفِيظٌ عَلِيمٌ} (يوسف : 55)

55- Yusuf (peace be upon him) said to him: Make me responsible for the treasury house of the country which is under your disposal for I am an honest keeper, and knowledgeable of disposing its affairs and knowledgeable of account.

Yusuf said that because of the coming years of famine which he can manage.

It is permissible for a person to show his knowledge for the one who ignores it.