To do anything ​ — whether it is good or bad — ​ one must set one’s mind on it. People who constantly set their minds on the things of the flesh soon develop a mental attitude or inclination that is totally focused on the things of the flesh.
قَبْلَ أَنْ يَقُومَ ٱلْمَرْءُ بِعَمَلٍ مَا ،‏ جَيِّدًا كَانَ أَمْ رَدِيئًا ،‏ عَلَيْهِ أَوَّلًا أَنْ يُوَجِّهَ فِكْرَهُ إِلَيْهِ .‏