It is reported that Ḥabīb b. ʿUbayd – Allāh have mercy on him – said:
Learn knowledge, understand it and benefit from it (live by it); and do not study it in order to decorate yourself with it, for if you live long you will likely see a time when knowledge will be used for beautification like a man beautifies himself with his garments.
Ibn Al-Mubārak, Al-Zuhd wa Al-Raqāʾiq no. 1056.