سنن النسائي

It was narrated that 'Amr bin Taghilb said: "The Messenger of Allah (ﷺ) said: 'One of the portents of the Hour will be that wealth becomes widespread and abundant, and trade will become widespread, but knowledge will disappear. A man will try to sell something and will say: "No, not until I consult the merchant of banu so and so: and People will look throughout a vast area for a scribe and will not find one." (Sahih )