If you believe in the future life and, instead of preparing for it, sell it in order to buy this world, then that is folly! You do not normally sell … - Al-Ghazali

"فلو وجد العالم عاميا يتعاطى له غسل الثياب محتاطا فهو أفضل فإنه بالإضافة إلى التساهل خير وذلك العامي ينتفع بتعاطيه إذ يشغل نفسه الأمارة بالسوء بعمل المباح في نفسه فيمتنع عليه المعاصي في تلك الحال والنفس إن لم تشغل بشيء شغلت صاحبها "
من كتب أسرار الطهارة

It is related that Satan came before Yahyâ . The latter saw that Satan had plucks of everything on his body. He asked him: “O Satan! What are these plucks?” He replied: “These are the desires with which I hunt mankind.” Yahyâ asked: “Do you have any of my plucks there?” He replied: “Perhaps you ate a stomach full which caused you to feel heavy and uncomfortable in offeringsalâh and remembering Allâh .” Yahyâ asked: “Is there anything else?” He replied: “No.” Yahyâ said: “I take an oath that I will never fill my stomach with food.” Satan said to him: “I take an oath that I will never advise a Muslim.” Among them is the love to have beautiful utensils, clothing and to adorn and decorate the house. When Satan sees that this quality has overpowered the heart of a particular person, he settles down and establishes himself in that person’s heart. He then continually invites him towards building the house, beautifying its roofs and walls, expanding it, etc. He also invites him towards beautifying himself with clothing and animals. He causes the person to undergo losses throughout his life in fulfilling all these demands. Once he gets him involved in all this, he does not have to go that person a second time because these very demands [and desires] lead him to fulfil other demands. This continues till his death. He thus dies in the path of Satan and in following his desires. An evil destiny is thus feared from all this. We seek refuge in Allâh

[K]nowledge that is not Infallible is not certain knowledge.